LI  B  R.AFLY 

OF  THE 

UNIVERSITY 
Of    ILLINOIS 

630.7 

IL6b 
no.  31-  ^o 


&QN  CIRCULATING 


CHECK  FOR  UNBOUND 
COPY 


.CIRCULATING 


CHECK  FOR  UNBOUND 
CIRCULATING  COPY 


UNIVERSITY  OF  ILLINOIS, 

Agricultural  Experiment  Station. 


URBANA,  APRIL,  i896. 


BULLETIN  NO.  43. 


COMPOSITION  AND  DIGESTIBILITY  OF  CORN  ENSILAGE, 

COW  PEA  ENSILAGE,  SOJA  BEAN  ENSILAGE, 

AND  CORN-FODDER. 

[For  explanations  of  technical  terms  and  information  concern- 
ing the  uses  of  food  constituents,  the  reader  is  referred  to  the 
Appendix.] 

METHODS  USED  IN  DIGESTION  EXPERIMENTS. 

The  general  method  of  conducting  a  digestion  experiment  is 
easily  understood.  The  animal  is  fed  a  weighed  amount  of  food, 
the  composition  of  which  is  determined  by  analyzing  a  sample  of 
it.  Any  part  of  the  food  which  the  animal  does  not  eat  is  col- 
lected, weighed,  and  analyzed.  By  subtracting  the  amounts  of 
the  different  nutrients  in  the  refuse  from  the  amounts  fed,  exactly 
what  the  animal  has  eaten  is  determined.  Then  by  collecting, 
weighing,  and  analyzing  the  dung  which  is  excreted  and  subtract- 
ing the  amounts  found  from  the  amounts  which  were  eaten,  we 
learn  what  amount  of  each  nutrient  has  been  digested.  By  com- 
paring the  amount  digested  with  the  amount  eaten  we  determine 
what  per  cent,  of  each  nutrient  has  been  digested.  This  per  cent, 
is  the  digestion  coefficient. 

ANIMALS  EMPLOYED. 

Four  high  grade  shorthorn  steers,  about  two  years  old  and 
I,IOO  pounds  average  live  weight,  were  selected  with  which  to 
carry  out  the  following  experiments.  Usually  digestion  experi- 
ments are  made  with  not  more  than  two  animals,  and  often  with 
only  one.  By  using  four  animals  it  was  expected  (i)  that  any 

181 


182  11ULLETIN    NO.   43.  [April, 

errors  with  the  individual  animals  would  be  detected  ;  (2)  that, 
if  there  is  a  difference  in  the  digestive  powers  of  the  dif- 
ferent animals,  it  would  become  evident;  and  (3)  that  the  results 
if  satisfactory  would  be  thoroughly  trustworthy.  The  same  four 
steers  were  used  in  each  of  the  four  experiments;  that  is,  with 
corn  ensilage,  cow  pea  ensilage,  soja  bean  ensilage,  and  corn- 
fodder.  These  steers  were  known  in  the  records  of  the  agricul- 
tural department  as  No.  53,  No.  54,  Roan,  and  No.  57,  and  they 
are  so  designated  in  this  bulletin. 

METHOD  OF  FEEDING. 

In  order  to  be  sure  that  no  other  foods  were  in  the  alimentary 
canal  the  steers  were  fed  during  a  preliminary  period  of  one  week 
on  the  same  kind  of  food  as  that  used  in  the  experiment,  care  be- 
ing taken  that  they  obtained  no  trace  of  any  other  food  ;  then  the 
experiment  proper  was  begun.  The  steers  were  fed  regularly 
twice  a  day.  For  each  feed  a  sufficient  quantity  was  taken  and 
thoroughly  mixed.  From  this  a  sample  was  reserved  and  four 
separate  portions  were  weighed  out  for  the  steers.  The  reserved 
samples  were  kept  in  tight  vessels  until  the  fourth  feed  had 
been  given  ;  then  they  were  mixed  together,  placed  in  a  meat 
chopper  and  cut  fine,  and  from  this  a  sample  representing  the 
average  feed  for  two  days  was  taken  for  analysis. 

The  steers  were  fed  all  they  would  eat  reasonably  clean.  It 
was  desired  to  learn  the  digestibility  of  the  foods  when  eaten  un- 
der these  conditions,  which  correspond  as  nearly  as  it  was  possible 
to  make  them  to  the  methods  of  feeding  in  ordinary  practice  by 
stock  feeders.  Often  in  digestion  experiments  the  animals  are 
given  much  less  food  than  they  would  ordinarily  eat,  so  little,  in 
fact,  that  they  eat  all  they  receive,  leaving  no  refuse  whatever. 
Of  course,  this  avoids  the  necessity  of  collecting  and  analyzing 
the  refuse,  but  it  is  well  known  that  with  most  coarse  food-stuffs 
'an  animal  must  usually  be  kept  in  a  half-starved  condition  to  com- 
pel it  to  eat  the  food  perfectly  clean  ;  and  it  is  certainly  ques- 
tionable whether  results  obtained  under  such  conditions  fairly 
represent  the  digestibility  of  the  food  as  ordinarily  fed. 

The  refuse  (uneaten  food)  from  each  steer  was  collected,  and 
at  the  end  of  two  days  each  steer's  refuse  was  weighed,  mixed, 
cut,  and  sampled  for  analysis. 

COLLECTING  THE  DUNG. 

Usually  in  digestion  experiments  the  animals  are  made  to 
wear  continually  a  close-fitting  harness  by  which  a  bag  is  held  in 


1896.]  DIGESTION    KXI'KKIMKNTS.  183 

position  to  catch  the  dung  as  it  falls.  In  our  experiments  no  har- 
ness was  used.  The  steers  were  kept  in  Bidwell  stalls  without 
being  tied.  These  stalls  are  adjustable  in  length  by  a  movable 
box  manger.  The  width  allows  the  animal  to  lie  down  comfortably 
but  not  to  turn  around  ;  and  by  a  rope  across  the  back  end  the  ani- 
mal is  prevented  from  backing  out  of  the  stall.  Just  back  of  the 
hind  feet  was  a  drop  of  about  six  inches  to  receive  the  dung.  The 
steers  were  bedded  with  sawdust,  which  was  covered  with  matting 
tacked  to  the  floor  to  keep  it  in  place.  The  urine  was  absorbed 
by  the  sawdust,  which  was  changed  as  often  as  necessary.  Only 
every  other  stall  was  used  ;  and,  as  the  Bidwell  stalls  have  one  side 
made  to  swing  open  on  a  hinge,  it  was  easy  to  change  the  sawdust 
and  to  keep  the  stalls  in  good  order. 

During  the  day  the  steers  were  attended  almost  constantly, 
and  the  dung  was  taken  up  from  the  drop  at  frequent  intervals  by 
means  of  a  spatula  and  a  small  scoop  and  kept  in  covered  vessels. 
During  the  night  from  about  10  o'clock  p.  m.  till  5  o'clock  a.  m. 
the  steers  were  left  alone,  but  usually  they  lay  quiet,  and  it  was  a 
common  thing  to  find  them  at  5  a.  m.  still  lying,  and  each  with 
several  pounds  of  dung  in  the  drop  which  they  had  voided  without 
rising.  Great  care  was  taken  from  the  beginning  to  the  end  of 
the  experiment  that  the  drop  should  be  kept  clean  from  foreign 
matter  and  that  no  dung  should  be  lost. 

It  may  seem  to  some  that  it  is  not  possible  to  let  dung  fall 
upon  a  clean,  smooth  floor  and  take  it  up  again  with  a  high  degree 
of  accuracy.  Experiments  were  made  to  determine  this.  About 
35  pounds  of  dung  were  allowed  to  fall  in  small  quantities  from  a 
height  of  four  feet,  each  being  taken  up  before  the  next  small 
quantity  was  allowed  to  fall.  In  two  trials  the  average  loss 
was  one-fourth  of  an  ounce.  In  three  trials  on  34  pounds  of  a 
different  sample  and  on  a  different  day  the  average  loss  was  one- 
third  of  an  ounce.  The  dung  was  then  simply  transferred  from 
one  vessel  to  another,  about  the  same  length  of  time  being  used 
as  had  been  taken  in  the  other  trials,  and  it  was  found  that  the  loss 
of  weight  by  the  evaporation  of  moisture  was  one-fourth  of  an 
ounce.  Evidently  this  method  of  collecting  the  dung  admits  of  a 
higher  percentage  of  accuracy  than  many  of  the  determinations  in 
its  subsequent  analysis. 

Experiments  with  cattle  have  shown  that  an  average  of  about  24 
hours  is  required  for  food  to  pass  through  the  alimentary  canal, 
although  there  are  wide  variations.  In  our  experiments  the  col- 
lection of  dung  was  commenced  24  hours  after  the  beginning  of 
the  experiment,  because  it  is  evident  that  the  composition  of  a 
sample  of  dung  depends  upon  the  composition  of  the  food  eaten 


184  BULLETIN  NO.  43.  [April, 

the  previous  day  rather,  than  upon  the  composition  of  the  food 
eaten  at  the  time  the  dung  is  voided.  While  irregularities  in 
voiding  the  dung  may  still  introduce  errors,  yet  if  the  experiment 
is  carried  on  for  a  sufficient  length  of  time,  large  amounts  of  mate- 
rial are  collected  and  such  possible  errors  become  insignificant. 

After  the  preliminary  feeding  the  digestion  experiments 
proper  were  begun,  and  continued  for  seven  days  ;  but  the  dung 
was  not  collected  during  the  first  day  of  the  seven,  and  no  analyses 
were  made  of  the  feed  or  refuse  of  the  seventh  day  ;  thus  the  time 
actually  corresponds  to  a  period  of  six  days.  The  importance  of 
allowing  time  for  the  material  to  pass  through  the  alimentary 
canal  is  evident  (i)  whenever  the  feed  is  not  strictly  uniform  and 
it  is  necessary  to  take  a  sample  of  every  feed  for  analysis,  as,  in 
fact,  is  usually  done  in  digestion  experiments ;  and  (2)  whenever 
the  composition  of  the  refuse  is  not  uniform  from  day  to  day,  for 
upon  the  composition  of  both  feed  and  refuse  depends  the  com- 
position of  the  food  eaten. 

METHODS  OF  ANALYSIS. 

The  fresh  samples  as  brought  from  the  barn  were  weighed  and 
then  reduced  to  the  air-dry  condition,  first  by  drying  the  samples 
at  about  50°  C.,  and  then  allowing  them  to  remain  exposed  to  the 
air  at  the  ordinary  temperature  till  the  weight  became  practically 
constant.  They  were  then  ground  to  pass  through  a  millimeter 
sieve,  placed  in  well  stoppered  bottles,  and  thoroughly  mixed. 
The  hygroscopic  moisture  was  determined  by  drying  a  2-gram 
sample  in  a  current  of  dry  hydrogen  gas  until  the  loss  in  weight 
became  less  than  one  milligram  per  hour.  At  the  temperature  of 
boiling  water  this  required  about  20  hours,  but  at  105°  C.  the  same 
results  were  obtained  in  about  one-third  of  that  time.  This  tem- 
perature was  obtained  by  using  a  reflux  condenser,  and  an  aqueous 
solution  of  glycerol  instead  of  water. 

The  final  analysis  was  made  by  the  methods  adopted  by  the 
Association  of  Official  Agricultural  Chemists  (Bull.  No.  43,  U.  S. 
Dep't  of  Agr.,  Div.  of  Chem.).  The  details  of  the  methods  were 
worked  out  and  tested  until  a  satisfactory  degree  of  accuracy  was 
obtained.  All  analyses  were  made  in  duplicate. 

The  ash  was  determined  by  burning  to  constant  weight  at  a 
low  red  heat  in  a  muffle  furnace. 

Kjeldahl's  method  was  employed  for  the  determination  of 
nitrogen,  and  the  protein  was  determined  by  multiplying  the 
amount  of  nitrogen  by  the  factor  6.25.  The  limit  of  error  allowed 
in  the  nitrogen  determination  was  one  per  cent,  of  the  amount 
determined. 


1896.]  DIGESTION   EXPERIMENTS.  185 

The  fat  was  determined  in  the  sample  which  had  been  dried 
in  the  determination  of  hygroscopic  moisture.  The  substance  to 
be  extracted  was  placed  in  a  glass  cylinder  whose  bottom  consisted 
of  a  piece  of  fat-free  hardened  filter  paper,  firmly  tied  over  the 
lower  end  of  the  cylinder  with  wire.  The  cylinder  was  then  placed 
in  a  Soxhlet  extraction  tube,  and  the  fat  extracted  with  absolute 
ether,  which  had  been  purified  by  distilling  over  a  coil  of  wire  made 
from  metallic  sodium,  and  had  been  kept  over  the  same  metal. 
The  fat  was  filtered  as  it  passed  through  the  paper.  The  limit  of 
error  was  reduced  to  below  one  milligram. 

The  fiber  was  determined  in  the  fat-free  sample  by  extrac- 
tion with  the  1.25  per  cent,  acid  and  alkaline  solutions,  the  first 
filtration  being  made  with  Schleicher  and  Schiill's  hardened  filter 
paper,  and  the  second  with  an  asbestos  filter.  The  limit  of  varia- 
tion between  duplicate  determinations  of  fiber  was  kept  below  one 
per  cent,  of  the  amount  determined. 

Three  composite  samples  of  the  feed  were  analyzed  in  each 
experiment,  thus  showing  the  average  composition  of  the  feed  for 
three  periods  of  two  days  each.  This  method  shows  any  marked 
variation  in  the  composition  of  the  feed.  Two  composite  samples 
were  made  of  the  refuse  from  each  steer,  one  for  a  period  of  two 
days,  and  the  other  for  a  period  of  four  days.  The  dung  from  each 
steer  was  also  made  into  two  composite  samples,  the  first  for  two 
days  and  the  second  for  a  four  days'  period. 

Daily  records  were  kept  throughout  the  experiments  of  the 
weights  of  the  steers,  the  amounts  of  water  drunk,  and  the  tem- 
perature of  the  barn;  but,  as  these  records  show  no  important  con- 
nection with  the  questions  under  investigation,  they  are  not  pub- 
lished. 

DIGESTIBILITY  OF  CORN  ENSILAGE. 

The  digestibility  of  corn  ensilage  by  cattle  has  been  deter- 
mined by  three  other  experiment  stations,  and  one  of  the  reasons 
for  choosing  that  food  with  which  to  begin  these  digestion  ex- 
periments was  to  test  the  methods  of  work  before  taking  up  lines 
which  had  never  been  investigated.  The  feed  was  only  a  fair 
sample  of  corn  ensilage  made  from  several  varieties  of  corn. 

The  essential  data  of  the  experiments  are  given  in  Tables  I 
and  2. 

NOTE. — The  computations  in  these  experiments  and  in  those 
which  follow  were  made  chiefly  by  five  place  logarithms  (checked 
by  Thacher's  calculating  instrument),  and  because  of  this  the  final 
results  are  given  with  a  h.igher  degree  of  accuracy  than  they  can 
be  obtained  by  using  the  data  here  presented.  For  example,  the 
per  cent,  of  protein  in  the  dry  matter  of  the  feed  for  Jan.  6th  and 


1 86 


BULLETIN    NO.   43. 


[April, 


7th  is  given  in  Table  I  as  10.07,  while  the  per  cent,  actually  found 
was  10.065,  and  it  was  the  logarithm  of  10.065  which  was  used  in 
making  the  computations.  If  10.07  be  used  a  slight  discrepancy 
will  appear,  because  a  slight  error  will  be  introduced. 

TAHLE  i.  NUMBER  OF  POUNDS  (BOTH  FRESH  AND  DRY)  OF  CORN  ENSILAGE  FED,  OF 
REFUSE,  AND  OF  DUNG,  FOR  EACH  STEER  ;  AND  ALSO  THE  PERCENTAGE  COMPOSI- 
TION OF  THE  DRY  MATTER. 


Date. 

Amounts, 
pounds. 

Composition  of  dry  matter, 
percentages. 

1895. 

Fresh 
sub- 
stance. 

Dry 
matter 

Ash. 

Pro- 
tein. 

Fat. 

Fiber. 

Car- 
bohy- 
drate 
extract 

Steer  No. 


Feed  
Feed  
Feed  

Jan.  2-3  
Jan.  4-5  
Jan.  6-7  .... 

148.00 
134.00 
125.00 

37.423 
36.541 
36.287 

6.58 
6.98 
8.07 

9.92 
9.92 
10.07 

2.90 

2.87 
2.70 

22.92  57.68 
21.89  58.34 

22.21  56  95 

Refuse  

Jan.  2-3  . 
Jan.  4-7  

22.  13 
49-83 

4.288 
IO.O39 

5.98 
6.79 

9.66 
9-54 

1.04 
-74 

28.12  55-2O 
29.25  53.68 

Refuse  

Dung  
Dung  

Jan.  3-4  .... 
Jan.  5-8  .... 

77.81 
163.26 

11.923 

24.815 

1  3  --P4 
13-77 

12  73 
12.75 

1.71 

1.48 

25.57!  46'95 
24.42;  47.58 

Steer  No.  54. 


Feed  
Feed  
Feed  

Jan.  2-3  .... 
Jan.  4-5  
Jan.  6—7  .... 

158.00 
137.00 
125.00 

39-951 

37-359 
36.287 

6.58 
6.98 
8.07 

9.92 
9.92 
10.07 

2.90 
2.87 
2.70 

22.92 
21.89 

22.21 

57-68 
58.34 
56.95 

Refuse  
Refuse  

Jan.  2-3  .... 
Jan.  4-7  .... 

25.06 
42.94 

5.260 
8.911 

6.00 
6.67 

9.61 
9-52 

1-43 
•79 

27.79 
29.36 

55-14 
53-66 

Dung  
Dung  

Jan.  3-4  .... 
Jan.  5-8  .... 

71.63 

157.87 

11.421 
26.421 

11.46 
12.89 

12.44 

12.85 

1-73 
1.70 

24.27 

23.38 

50.10 
49-18 

Steer  Roan. 


Feed  
Feed  
Feed  

Jan.  2-3  .... 
Jan.  4-5  
Jan.  6-7  

158.00 
138.00 
130.00 

39-951 
37.633 
37-739 

6.58 
6.98 
8.07 

9.92 
9.92 
10.07 

2.90 
2.87 
2.70 

22.92 
21.89 

22.21 

57-68 
58.34 
56.95 

Refuse  
Refuse  

[an.  2-3  .... 
Jan.  4-7  .... 

24.00 
41.44 

5.206 
9.284 

6.  ii 

7.06 

9.69 

9.48 

1-73 
1.24 

26-75 
28.15 

55.72 
54-07 

Dung  
Dung  

Jan.  3-4  
Jan.  5-8  .... 

90-57 

178  13 

13.268 
27.241 

11.77 
12.57 

11.70 
11.91 

i-59 
1.44 

25.90 
25.64 

49.04 

48.44 

Steer  No. 


Feed  ;  Jan.  2-3  .... 
Feed  Jan.  4-5  .... 
Feed  Jan.  6-7  .... 

162.00 
142.00 
138.00 

40.963 

38.724 
40  .  062 

6.58 
6.98 
8.07 

9-92 
9.92 
10.07 

2.90    22.92 
2.87!  21.89 

2.70;    22    21 

57-68 
58-34 
56.95 

Refuse  Jan.  2-3  .... 
Refuse  Jan.  4-7  .... 

30-88 
55-00 

6-449 
11.714 

6.31 
6.89 

9-93 
9.61 

1.49 
I.I? 

26.68 
28.61 

55-59 
53-72 

Dung  Jan.  3-4  .... 
Dung  Jan.  5-8  .... 

77-56 
149  39 

12.205 
24.894 

12.75 
14.01 

12.15 
12.76 

i-73 
1-65 

24-38 

23.  12 

48.99 
48.46 

From  the  data  given  in  Table  I  we  are  able  to  compute  the 
digestion  coefficients  for  each  nutrient.  Take,  for  example,  the 
protein  in  the  experiment  with  Steer  No.  53.  During  the  two 
days,  Jan.  2d  and  3d,  Steer  No.  53  was  given  148  Ib.  of  corn 
ensilage,  but  after  subtracting  the  water  it  contained  there 
remained  37.423  Ib.  of  dry  matter.  Of  this  37.423  Ib.  9.92  per 


1896.]  DIGESTION   EXPERIMENTS.  187 

cent,  was  protein.  By  multiplying  the  number  of  pounds  of  dry 
matter  by  the  per  cent,  of  protein  which  it  was  found  by  analysis 
to  contain,  we  have  the  number  of  pounds  of  protein  fed  to  Steer 
No.  53  during  the  two  days'  period,  Jan.  2d  and  3d,  and  in  like 
manner  the  amounts  of  protein  fed  during  Jan.  4th  and  5th,  and 
during  Jan.  6th  and  7th  are  computed. 
Thus: 

Dry  matter,  Per  cent,  of 

pounds.  protein. 

Jan.  2-3 37»423  9-92 

Jan.  4-5 36,541  9-92 

Jan.  6-7 36,287  10.07 

Total  protein  fed  during  six  days 10.989 

In  a  similar  way  we  find  that  the  total  amount  of  protein  in 
the  refuse  during  the  six  days'  period,  Jan.  2d  to  Jan.  7th,  was 
1.372  Ib.  By  subtracting  this  from  the  amount  of  protein  fed 
we  find  that  9.617  Ib.  of  protein  were  eaten.  Now  by  com- 
putation we  find  the  amount  of  protein  in  the  dung  for  the  six 
days,  Jan.  3d  to  Jan.  8th,  was  4.682  Ib.;  and  this  subtracted  from 
the  amount  eaten  leaves  4.935  Ib.  of  protein  digested.  Dividing 
the  number  of  pounds  of  protein  digested  by  9.617,  the  number  of 
pounds  eaten,  we  have  51.32  per  cent,  of  the  total  protein  eaten. 
That  is,  51.32  is  the  digestion  coefficient  of  the  protein  as  deter- 
mined by  Steer  No.  53.  The  digestibility  of  each  nutrient  was 
determined  by  the  same  methods. 

Table  2  gives  the  results  in  full  for  each  steer  for  the  six  days' 
period. 


1 88 


BULLETIN   NO.   43. 


[April, 


TABLE  2.  NUMBER  OF  POUNDS  OF  EACH  NUTRIENT  IN  THE  CORN  ENSILAGE  FED,  IN 
THE  REFUSE,  AND  IN  THE  DUNG,  DURING  A  PERIOD  OF  Six  DAYS  ;  AND  ALSO  THE 
DIGESTION  COEFFICIENT  OF  EACH  NUTRIENT. 


Dry 

matter. 

Ash. 

Protein. 

Fat. 

Fiber. 

Carbo- 
hydrate 
extract. 

Steer  No. 


Corn  ensilage  fed  

110.251 

7-Q4O 

lO-OSO 

3-  no 

24.616 

61.  ^76 

Amounts  refused  

14.327 

.038 

I  .  "372 

.  IIQ 

4.  142 

7   7c6 

Amounts  eaten  

Q5.Q24 

7.  002 

O.6l7 

2  .QQI 

2O  .  4Q4 

56.820 

Dung  excreted  

36.738 

4..Q72 

4.682 

.  16Q 

q.  no 

17.405 

Amounts  digested    .... 

59  1  86 

2   030 

40*^5 

2    422 

II    184 

an   /lie 

Per  cent,  digested  .  .  . 

61.70 

28.99 

51.32 

80.98 

55.55 

69.37 

Steer  ATo. 


Corn  ensilage  fed  

III.  C1Q7 

8.164 

n  .321 

3.2O7 

25.  38<i 

65.  s2O 

Amounts  refused  

14.  171 

QIO 

I.  3"i3 

.  147 

4.O7Q 

7.682 

Amounts  eaten  

00.426 

7.254 

0.968 

T,.o6o 

21.306 

57.838 

VI  .  842 

4.7l6 

4.816 

.646 

8.048 

18.716 

Amounts  digested  .... 

61.584 

2.  538 

5.  1^2 

2.4.14. 

12.  3"i8 

30,    122 

Per  cent,  digested  

61.94 

34.99 

51.69 

78.89 

58.00 

67.64 

Steer  Roan. 


Corn  ensilage  fed  ...    . 

TTK     121 

8  300 

1  1  .  4Q  5 

0.254 

26    277 

65    QQ7 

I4.4QO 

.0,74 

1.385 

.205 

4.OO6 

7.Q2O 

100.  833 

7  .  ^26 

IO.  IIO 

•2    O4Q 

22.271 

58.O77 

4O.  5OQ 

4.087 

4.7Q7 

.604 

IO.42O 

IQ    7OI 

Amounts  digested  

60.324 

2-339 

5.313 

2.445 

11.851 

38.376 

Per  cent,  digested  .... 

59.83 

31.93 

52.55 

80.19 

53.21 

66.08 

Steer  No.  57. 


Corn  ensilage  fed  

IIQ.74Q 

8.620 

II  .Q17 

3.  377 

26.071 

68.835 

Amounts  refused  

18.163 

1.  214 

1.766 

.233 

C.O73 

0.877 

Amounts  eaten  

101.586 

7.415 

10.  171 

3-  144 

21.898 

58.958 

Dung  excreted  

37.OQQ 

5.  043 

4.66O 

.622 

8.731 

18.043 

Amounts  digested  

64.487 

2.372 

5.511 

2.522 

13.167 

40.915 

Per  cent,  digested   .  .  . 

63.48 

31.99 

54.18 

80.22 

60.13 

69.40 

In  order  to  compare  the  digestibility  of  corn  ensilage  as  de- 
termined at  this  station  with  the  results  obtained  at  other  experi- 
ment stations  the  following  table  is  published.  This  presents  the 
results  of  all  the  experiments  which  have  been  made  in  the  United 
States  to  determine  the  digestibility  of  corn  ensilage  by  cattle. 

The  Pennsylvania  Station  has  made  10  separate  determina- 
tions, using  five  different  samples  of  corn  ensilage,  the  digestibility 
of  each  sample  being  determined  with  two  animals  as  indicated  in 
the  table.  Wisconsin  has  made  two  determinations,  North  Caro- 
lina one,  and  Illinois  four,  as  given  above. 

Table  3  gives  all  of  these  determinations  separately,  and  also 
the  averages  obtained  from  them. 


1896.] 


DIGESTION   EXPERIMENTS. 


189 


TABLE  3.     DIGESTIBILITY  OF  CORN  ENSILAGE  BY  CATTLE,  AS  SHOWN  BY  ALL  EXPER- 
IMENTS MADE  IN  THK  UNITED  STATES. 


Experiments  made  by: 

Trial 

No. 

Animals 
employed. 

Dry 
matter 

Ash. 

Pro- 
tein. 

Fat. 

Fiber. 

Car- 
bohy- 
drate 
extract 

Pennsylvania  

i 
2 

Steer  No.  i  .  . 
Steer  No.  2  .  . 

72.1 
73-6 

30.7 
43-6 

60.4 
62.8 

89.7 

87.7 

79.6 
80.6 

72.1 

72.8 

Pennsylvania  

Pennsylvania  

3 
4 

Steer  No.  i  .  . 
Steer  No.  2  .  . 

59-9 
66.7 

28.1 
40-3 

44.0 
47-9 

85.0 
87.0 

60.  1 
67.0 

62.9 
70.0 

Pennsylvania  

Pennsylvania  

5 
6 

Steer  No.  I  .  . 
Steer  No.  2  .  . 

62.2 
60.5 

38.7 
18.7 

47-5 
43-5 

86.0 
86.4 

55-9 
55-6 

66.6 
66.2 

Pennsylvania  .        ... 

Pennsylvania  

7 

8 

Steer  No.  i  .  . 
Steer  No.  2  .  . 

68.1 
60.4 

36.0 
18.6 

44.0 
32.4 

76.6 

74-7 

77-6 
71.6 

69.7 
59-8 

Pennsylvania  

Pennsylvania         .... 

9 
10 

Steer  No.  I  .  . 
Steer  No.  2  .  . 

65-9 
66  '.2 

46.4 
39-7 

48.5 
45-o 

85.2 
83.7 

77-8 
72.7 

70.3 
66.1 

Pennsylvania     

Average  of  ten  determinatio 

ns  

65.6 

34.1 

47.6 

84.2 

69.9 

67.7 

Wisconsin  

; 

Cow  No.  i  .  . 
Cow  No   2  .  . 

63-4 
62.9 

21.2 

18.2 

52.2 
55-3 

82.7 
82.1 

48.9 
45-4 

71.6 
71.8 

Wisconsin  

Average  of  two  determinatit 

ns     

63.2 

19.7 

53.8 

82.4 

47.2 

71.7 

North  Carolina  

i 

Cow  

53.2 

26.9 

34.4     66.0 

43.2 

60.5 

Illinois  

i 

2 

3 
4 

Steer  No.  53. 
Steer  No.  54. 
Steer  Roan  .  . 
Steer  No.  57. 

61.7 
61.9 
59-8 
63-5 

29.0 
35-0 

31-9 
32.0 

51.3 
51-7 
52.6 
54-2 

81.0 
78.9 
80.2 
80.2 

55-6 
58.0 
53-2 
60.  i 

69.4 
67.6 
66.1 
69.4 

Illinois      

Illinois  .          

Illinois  

Average  of  four  determinatic 

>ns  

61.7 

32.0 

52.4      80.1 

56.7 

68.1 

Average  of  seventeen  determinations  

63.6 

31.5 

48.6     81.9 

62.6 

67.8 

Evidently  trials  No.  I  and  No.  2  by  the  Pennsylvania  Station 
give  results  which  are  too  high  for  the  digestibility  of  corn  ensilage, 
while  the  trial  by  the  North  Carolina  Station  gives  results  as  much 
too  low.  Excluding  these  three  determinations  would  slightly 
reduce  most  of  the  coefficients  in  the  general  average,  and  it  would 
bring  the  average  of  the  Pennsylvania  Station  considerably  nearer 
to  the  general  average. 

The  results  obtained  by  the  Illinois  Station  agree  well  among 
themselves  and  also  with  the  general  average.  The  coefficients 
for  protein  are  somewhat  above  the  average  but  they  are  almost 
identical  with  the  Wisconsin  determinations,  and  fall  within  the 
range  of  the  results  from  the  Pennsylvania  Station.  The  Illinois 
coefficients  for  fiber  are  below  the  general  average  but  they  are 
nearer  it  than  is  the  average  from  any  other  station. 

DIGESTIBILITY  OF  COW  PEA  ENSILAGE. 

The  cow  pea  is  a  forage  plant  which  is  already  attaining  some 
prominence  in  Illinois.  It  is  a  leguminous  plant,  and,  by  means  of 
the  bacteria  which  inhabit  its  roots,  it  is  enabled  indirectly  to 
draw  upon  the  free  nitrogen  of  the  air  for  a  part  of  its  food  supply. 


190 


IH'LLETIN    NO.    43. 


{April, 


In  this  respect  it  resembles  clover,  and  it  will  prove  of  great  value 
in  improving  the  soil.  Like  clover,  the  cow  pea  plant  is  rich  in 
protein,  or  nitrogenous  matter,  and  this  indicates  that  it  may  have 
a  high  feeding  value  for  milk  production  and  similar  uses.  In  the 
form  of  ensilage  it  was  readily  eaten  by  the  steers. 

The  data  and  the  results  obtained  from  the  digestion  experi- 
ments with  cow  pea  ensilage  are  presented  in  Tables  4,  5,  and  6. 

TABLE  4.  NUMBER  OF  POUNDS  (BOTH  FRESH  AND  DRY)  OF  Co\v  PEA  ENSILAGE  FED, 
OF  REFUSE,  AND  OF  DUNG,  FOR  EACH  STEER;  AND  ALSO  THE  PERCENTAGE  COM- 
POSITION OF  THE  DRY  MATTER. 


Date. 

Amounts, 
pounds. 

Composition  of  dry  matter, 
percentages. 

1895. 

Fresh 
sub- 
stance. 

Dry 

matter 

Ash. 

Pro- 
tein. 

Fat. 

Fiber. 

Car- 
bohy- 
d  rate 
extract 

Steer  ATo. 


Feed  

Jan.  29-30  .  . 
Jan.  3i-Feb.  i 
Feb.  2-3  . 

176.00 
174.00 
168.00 

37.030 
38-352 
35-366 

II.  21 
II.O9 
11.13 

15.29 

I4-5I 
15.42 

2.99 
2.66 
3.02 

27-99 
27-43 
27-64 

42.52 
44-31 
42.79 

Feed  

Refuse  
Refuse        .      ... 

Jan.  29-30.  .  . 
Jan.  3i-Feb.  3 

10.50 
38.06 

2.316 

7-535 

7.67 

8.13 

10.45 
9.89 

.70 
•54 

42.62 
44-73 

38.56 
36.71 

Dung  .  .    
Dung  

Jan.  30-31.  .. 
Feb.  1-4  

68.47 
125.03 

13-968 
26.468 

19.44 
19.44 

16.45 

16.55 

2.86 
2.80 

30.85 
32.37 

30.40 

28.84 

Steer  No.  54. 


Feed  
Feed  

Jan.  29-30... 
Jan.  3i-Feb.  i 
Feb.  2-3  

181.00 
176.00 
173.00 

38.082 
38.792 
36.419 

II.  21 
II.O9 
II.  13 

15.29 
14.51 
15-42 

2-99 
2.66 
3.02 

27.99 

27-43 
27.64 

42.52 
44-31 
42-79 

Feed  

Refuse  
Refuse  ....  .... 

Jan.  29-30.  .  . 
Jan^3i-Feb.  3 

3-63 
24-13 

•855 
5-II4 

7-85)     9-75 

8.  Ill     10.20 

•79 
.60 

38.91 
42.32 

42.70 

38.77 

Dung  
Dung  

Jan.  30-31... 
Feb.  1-4  

7Q-53 

147.85 

15.003 
28.464 

19.65 
19.36 

16.30 
16.46 

2.90 
2.76 

32-i5 
31.01 

29.00 
30.41 

Steer  Roan. 


Feed  

Jan.  29-30.  .  . 
Jan.  3i-Feb.  i 
Feb.  2-3  

197.00 
187.00 
171.00 

41.449 
41.217 
35.998 

II.  21 
11.09 
11.13 

15.29        2.99 

14.51      2.66 
15.42      3.02 

27.99 

27-43 
27.64 

42.52 
44-31 
42.79 

Feed  

Refuse  
Refuse  

Jan.  29-30.  .  . 
Jan.  3i-Feb.  3 

15-25 
36.78 

3.520 

8.188 

7.64 

7-73 

10.44 
10.09 

.91 

•73 

39-70 
40.15 

41-31 
41-30 

Dung  
Dung  

Jan.  30-31... 
Feb.  1-4. 

87.25^15.910 
149.47:27.91-1 

19.64 

20.12 

15.90 
16.30 

2.80 
2.91 

32.21 
31.86 

29.45 

28.81 

Steer  No. 


Feed  
Feed  

Jan.  29-30.  .  . 
Jan.  3i-Feb.  I 
Feb.  2-3  

193.00 
187.00 
174.00 

40  .  607 
41.217 

36.629 

1  1  .  2  1 
11.09 
11.13 

I5-29 
14-51 
15.42 

2-99 
2.66 
3.02 

27-99 
27-43 
27.64 

42-52 
44-31 
42.79 

Feed  

Refuse  
Refuse  .... 

Jan.  29-30.  .  . 
Jan.  3i-Feb.  3 

10.25 
47-41 

2.336 
10.383 

8.08 
7.88 

IO.2O 
9.92 

.78 
.68 

40.65 
43-20 

40.29 
38-32 

Dung  
Dung  

Jan.  30-31... 
Feb.  1-4.  .. 

76.53 
134-94 

14-83$ 
27.387 

19.91 
20.54 

16.27 
16.45 

2.70 
3-13 

29  59 
30.12 

31-53 
29.76 

1 80.] 


DIGESTION   EXPERIMENTS. 


191 


TABLE  5.  NUMBER  OF  POUNDS  OF  EACH  NUTRIENT  IN  THE  Cow  PEA  ENSILAGE  FED, 
IN  THE  REFUSE,  AND  IN  THE  DUNG,  FOR  A  PERIOD  OF  six  DAYS,  WITH  EACH 
STEER;  AND  ALSO  THE  DIGESTION  COEFFICIENTS  OF  EACH  NUTRIENT. 


Dry 
nvatter. 

Ash. 

Protein. 

Fat. 

Fiber. 

Carbo- 
hydrate 
extract. 

Steer  No. 


Cow  pea  ensilage  fed  .  . 

110.748 

Q    8"U 

12.350 
.700 

16.678 

Q87 

3-194 

OS7 

30.659 

41C7 

47.867 

Amounts  eaten  

100.807 

IT  .  560 

I5.6QI 

1.  117 

26.  3O2 

jt    2O7 

Dung  excreted  

40.4.16 

7.860 

6.677 

1.  142 

12.877 

I  I  .  88O 

Amounts  digested  

60.461 

1.  700 

9.OI4 

I  .QQ"i 

1*1  .  J.25 

12.  127 

Per  cent,  digested  .  .  . 

59.92 

32.01 

57.45 

63.60 

51.04 

73.13 

Steer  N».  54. 


Cow  pea  ensilage  fed  .  . 

113.293 
^.060 

12.635 
482 

17.064 
•  605 

3.268 
038 

31-364 

2    J.O7 

48  962 

2    147 

Amounts  eaten   

107.124 

12.  IC1 

16.450 

1.  210 

28  867 

46  6m 

Dung  excreted  

43.467 

8.457 

7.  I2Q 

i  .220 

13.652 

II.OOQ 

Amounts  digested  

63.857 

1.6q6 

9.  110 

2.OIO 

is  .21s; 

33  606 

Per  cent,  digested  .  .  . 

59.50 

30.41 

56.69 

62.23 

52.71 

72.09 

Steer  Roan. 


Cow  pea  ensilage  fed..  . 
Amounts  refused  

118 
ii 

664 
708 

13 

•234 
.902 

17 

i 

.867          3 
•193 

421 
092 

32-855 
4.686 

51-287 
4.835 

Amounts  eaten  

106 
43 

956 
821 

12 

8 

•332 
•741 

16 

.674 
.081 

3 
i 

2 

329 

257 

28 
14 

169 
017 

46.452 
12.725 

Dung  excreted  

Amounts  digested  
Per  cent,  digested  .  .  . 

63 

135          3 

•591          9 

•593 

072 

14-152  i     33-727 

59 

03         29 

.12          57 

.53 

62 

24         50 

24 

72.61 

Steer  No. 


Cow  pea  ensilage  fed  .  . 
Amounts  refused  .  . 

nS-453 
12.710 

13.210        i7-335 
i.  008          1.268 

3-4I5 

.088 

32-793 
S  .414 

51.200 
4.Q2I 

Amounts  eaten  

10=;.  714 

12.  2O2           16.567 

1.  127 

27  .  mo 

46.27Q 

Dung  excreted  

42.226 

8.579             6.918 

1.257 

12.639 

I2.8l1 

Amounts  digested  

63.508 

3.623             9-649 

2.070 

14.720 

33.446 

Per  cent,  digested  .  .  . 

60.06 

29.69         58.24 

62.22 

53.80 

72.27 

TABLE  6.     DIGESTION  COEFFICIENTS  FOR  Cow  PEA  ENSILAGE  AS  OBTAINED  FROM 
EACH  STEER,  AND  ALSO  THE  AVERAGE  OF  THE  FOUR  DETERMINATIONS. 


Animals  employed. 

Dry 
matter. 

Ash. 

Protein. 

Fat. 

Fiber. 

Carbo- 
hydrate 
extract. 

Steer  No.  53  

59-9 

32.0 

17-  "5 

61.6 

SI  -O 

71.  i 

Steer  No.  54  

SQ-5 

10.4 

56.7 

62.2 

C2.7 

72.  I 

Steer  Roan  

59  -o 

2Q.  I 

C7  .  C. 

62.2 

5O    2 

72.6 

Steer  No.  57  . 

60.  1 

2Q    7 

58    2 

62.2 

51-3 

72.  1 

Average  of  four  

59.6 

30.3 

57.5 

62.6 

52.0 

72.5 

These  determinations  agree  well  and  the  results  are  very  satis- 
factory.    The    average    of    the    four   determinations    is    given    in 


IQ2  BULLETIN   NO.   43.  \April, 

Table  17,  page  205.  By  referring  to  that  table  and  comparing  these 
results  with  the  digestibility  of  clover  hay  it  will  be  found  that  the 
total  dry  matter  of  the  cow  pea  ensilage  is  about  7  per  cent,  more 
digestible  than  that  of  clover  hay,  and  the  protein  is  6  per  cent., 
the  fat  15  per  cent.,  the  fiber  5  percent.,  and  the  carbohydrate  ex- 
tract 13  per  cent,  more  digestible.  It  should  be  noted  that  the 
digestibility  of  clover  hay  was  determined  with  sheep,  although  it 
may  also  be  stated  that  most  authorities  agree  that  cattle  and 
sheep  have  equal  digestive  powers,  and  most  tables  of  digestion 
coefficients  are  given  for  ruminants,  no  distinction  being  made. 

In  Table  18,  page  205,  both  composition  and  digestibility  are 
considered,  and  it  is  shown  that  100  Ib.  of  the  dry  matter  of  cow 
pea  ensilage  furnishes  8  Ib.  of  protein  and  13,000  calories  of 
energy  above  that  furnished  by  100  Ib.  of  dry  matter  of  clover 
hay. 

No  other  determinations  of  the  digestibility  of  cow  pea  ensilage 
have  been  made  in  the  United  States,  nor  in  other  countries,  so 
far  as  I  have  been  able  to  learn. 

DIGESTIBILITY  OF  SOJA  BEAN  ENSILAGE. 

The  soja  bean  is  a  leguminous  plant,  which  has  been  introduced 
into  this  country  from  Japan.  Like  clover,  it  is  a  "  nitrogen 
gatherer,"  and  it  contains  a  high  percentage  of  protein.  It  has 
already  been  grown  as  a  forage  plant  to  some  extent  in  the  United 
States. 

The-data  and  results  obtained  from  the  digestion  experiments 
with  soja  bean  ensilage  are  given  in  Tables  7,  8,  and  9. 


1896.] 


DIGESTION   EXPERIMENTS. 


193 


TABLE  7.  NUMBER  OF  POUNDS  (BOTH  FRESH  AND  DRY)  OF  SOJA  BEAN  ENSILAGE 
FED,  OF  REFUSE,  AND  OF  DUNG,  FOR  EACH  STEER  ;  AND  ALSO  THE  PERCENTAGE 
COMPOSITION  OF  THE  DRY  MATTER. 


Date. 

Amounts, 
pounds. 

Composition  of  dry  matter, 
percentages. 

1 

Par 

1895. 

Fresh 
sub- 
stance 

Dry 
matter 

Ash. 

Pro- 
tein. 

Fat. 

Fiber. 

bohy- 
drate 

extract 

Steer  No. 


Feed      

Feb.  19-20  .  . 
Feb.  21-22  .  . 
Feb.  23-24  .  . 

131  .00 
130.00 
125.00 

3I-7I4 
3I-746 
30-412 

12.  6l 

15-87 
14-31 

11.49 
13.21 
13-94 

2.83 
3-i5 
3-40 

33-89 
30.26 
29.02 

39.18 
37-51 
39-33 

Feed  
Feed.    

Refuse  

Feb.  19-20  .  . 
Feb.  21-24  .  . 

17.16 
32-97 

4-843 
9.262 

7.26 

8.15 

6.56 
7.63 

.82 
.90 

51-27 
50.60 

34-09 
32.72 

Refuse  

Feb.  20-21  .  . 
Feb.  22-25  •  • 

60.03 
127.97 

12.828 
27.224 

19.99 
23-41 

13.04 
12.06 

3.82 
3-68 

32.48 
29.89 

30.67 
30.96 

Dung  

Steer  No. 


Feed  

Feb.  19-20  .  . 
Feb.  21-22  .  . 
Feb.  23-24  .  . 

138.00 
129.00 
103.00 

33-408 
3I-502 
25.061 

12.  6l 

15-87 
14-31 

11.49 
13.21 
13-94 

2.83 
3-15 
3-40 

33-89 
30.26 
29.02 

39-18 
37-51 
39-33 

Feed  

Feed  

Refuse  

Feb.  19-20  .  . 
Feb.  21-24  .  . 

17.88 
32.82 

4.942 
9.046 

7-85 

8.07 

7.00 

8.02 

.92 

1.04 

50.76 
49.62 

33-47 
33-25 

Refuse  

Feb.  20-21  .  . 
Feb.  22-25  •  • 

71.81 
I33-50 

13-301 
24.814 

19.27 

22.91 

12.52 
12.13 

3-55 
3-59 

33-66 
31.21 

31.00 
30.16 

Dung  

Steer,  Roan. 


Feed  

Feb.  19-20  .  . 
Feb.  21-22  .  . 
Feb.  23-24  .  . 

138.00 
137.00 
123.00 

33-408 

33-455 
29.927 

12.  6l 

15-87 
14-31 

11.49 
13.21 
13-94 

2.83 
3-15 
3-40 

33-89 
30.26 
29.02 

39.18 
37-51 
39-33 

Feed  

Feed  

Refuse  

Feb.  19-20  .  . 
Feb.  21-24  .  . 

I7.56 
32.19 

5-030 
9.151 

7.02 
7.61 

6-34 
7-74 

.66 
•97 

53-99 
50.13 

31-99 
33-55 

Refuse  

Dung  .  .        

Feb.  20-21  .  . 
Feb.  22-25  .  . 

72.53 
147.19 

12.973 

28.819 

20.55 
22.85 

13-25 
n-93 

3.61 

3-63 

32-25 
31-38 

30-34 
30.21 

Dung  

Steer  No. 


Feed  

Feb.  19-20  .  . 
Feb.  21-22  .  . 
Feb.  23-24  .  . 

IO2.OO 

86.00 

IOI.OO 

24.693 

2I.OOI 
24-573 

12.  6l 

15.87 
14-31 

11.49 
13.21 
13-94 

2.83 
3-i5 
3-40 

33-89 
30.26 
29.02 

39.18 
37-51 
39-33 

Feed  

Feed  

Refuse  

Feb.  19-20  .  . 
Feb.  21-24  .  . 

13.09 

15-47 

3-68c 
4.546 

7.00 

6.71 

6.58 

6-55 

•74 
.67 

52.00 

53-73 

33-68 
32-34 

Refuse  

Feb.  20-21  .  . 
Feb.  22-25  .  . 

50.78 
i  i  i  .  29 

10.440 
20.531 

20.09 

22.88 

12  43 
11.80 

3-32 
3.26 

33-38 
3I-48 

30.78 
30.58 

Dung  

194 


BULLETIN   NO,   43. 


[April, 


TABLE  8.  NUMBER  OK  POUNDS  OK  EACH  NUTRIENT  IN  THE  SOJA  BEAN  ENSILAGE 
KED,  IN  THE  REFUSE,  AND  IN  THE  DUNG,  DURING  A  PERIOD  OF  SIX  DAYS;  AND 
ALSO  THE  DIGESTION  COEFFICIENTS. 


Dry 
matter. 

Ash. 

Protein. 

Fat. 

Fiber. 

Carbo- 
hydrate 
extract. 

Steer  AT< 


Soja  bean  ensilage  fed.. 
Amounts  refused  

93-872 

14.    IO=; 

I3-392 
i  .  107 

12.079 
i  025 

2  -  93° 

I  21 

29.182 

7     1  60 

36.289 
4  681 

Amounts  eaten  

70.767 

12.285 

II  .054 

2.807 

22.OI3 

31  608 

Dun"  excreted   

40.0^2 

8.  cm 

-1   QS7 

I    40  1 

12.  TO1 

12  362 

Amounts  digested  

^Q  •  7  1  5 

3  •  34^ 

6.CQ7 

1.316 

Q.7IO 

iq.  246 

Per  cent,  digested.  .  .  . 

49.79 

27.24 

55.16 

46.88 

44.11 

60.89 

Steer  A"<>.    - 


Soja  bean  ensilage  fed.. 
Amounts  refused    

89.971 

13  988 

12.801 
1.118 

"•495 
i  .071 

2.789 
.  140 

28.129 
6  006 

34-757 
4661 

Amounts  eaten   

75.083 

11.683 

10.424 

2.64.0 

21  .  II'? 

1O    OQ4 

Dung  excreted   

38.115 

8.249 

4.675 

i  .  ^64 

12.222 

II    605 

Amounts  digested  

37-868 

3.4^4 

5.749 

1.285 

8.QI  I 

18.489 

Per  cent,  digested  .... 

49.84 

29  39 

55.15 

48.51 

42.17 

61.44 

Steer  Roan. 


Soja  bean  ensilage  fed.. 
Amounts  refused    

96.790 
14.  181 

13.807 

I  .O4Q 

12.432 
i  .027 

3.016 

.  122 

30.132 

7  .  -3Q2 

37-403 
4.681 

Amounts  eaten  

82.6O9 

12.758 

ii  .405 

2.804 

22.8lO 

32.722 

41  .702 

9.25O 

5.158 

I  .  514 

13.  227 

12.643 

Amounts  digested  

40.817 

3.508 

6.247 

1.380 

9.603 

20.079 

Per  cent,  digested  .  . 

49.41 

27  50 

54.77 

47.68 

42.06 

61  36 

Steer  No.  jf. 


Soja  bean  ensilage  fed.. 
Amounts  refused  

?o 

8 

267 
226 

9 

965 
563 

9.038 
•  S4O 

2 

196 
058 

21. 
4. 

856 
Tifi 

27 

2 

212 
7OQ 

62 

041 

Q 

402 

8.498 

2 

138 

17  . 

500 

24 

so** 

Dung  excreted    

3° 

971 

6 

795 

3.72O 

I 

£ 

Ol6 

Q 

()|S 

q 

492 

Amounts  digested    .... 

3i 

070 

2 

607 

4.778 

I 

122 

7- 

552 

15 

on 

Per  cent,  digested  .  .  . 

50 

08 

27 

73 

56.23 

52 

48 

43. 

15 

61 

26 

TABLE.  9.     DIGESTION  COEFFICIENTS  FOR  SOJA  BEAN  ENSILAGE  AS  OBTAINED  FROM 
KACH  STEER,  AND  ALSO  THE  AVERAGE  OF  THK  KOUR  DETERMINATIONS. 


Animals  employed. 

Dry 
matter. 

Ash 

Protein. 

Fat. 

Fiber. 

Carbo- 
hydrate 
extract. 

Steer  No.  53  

49  8 

27  .2 

55.2 

46    Q 

44-  ! 

60.  q 

Steer  No.  54  

49-8 

2Q.4 

55.2 

48.5 

42.2 

61  .4 

Steer  Roan  

4Q  .4 

27  .  5 

54-8 

47  .7 

42.  1 

61    4 

Steer  No.  57  

^O.  I 

27    7 

^6.2 

C2.  $ 

4-1  .  2 

61  .  ^ 

Average  of  four  

49.8 

28.0 

55.3 

48.9 

42.9 

61  2 

The  only  other  determinations  which  have  been  made  of  the 
digestibility  of  soja  bean  ensilage  are  those  reported  by  the  North 


1896.; 


DIGESTION    EXPERIMENTS. 


195 


Carolina  Station  in  Bulletin  No.  8/d.  The  determinations  were 
made  with  goats,  and  the  results  of  the  experiments  are  given 
below : 


Annuals  ungloved. 

Dry 
Ash. 
matter. 

1'rotein. 

Fat. 

Fiber. 

Carbo- 
hydrate 
extract 

Goat  No.  i  

52    •}       -       47  .  1 

71.3 

66.4 

47  .  1 

1C  .Q 

Goat  No.  2  

h£.>                 66.3 

80.2 

77-3 

62.5 

53.2 

From  these  results  it  appears  that  goats  are  able  to  digest  a 
higher  per  cent,  of  soja  bean  ensilage  than  cattle  ;  but  the  wide 
differences  shown  in  the  determinations  with  the  goats  indicate 
that  such  an  assumption  may  not  be  trustworthy. 

The  average  of  the  results  obtained  from  the  four  steers  is 
given  in  Table  17,  page  205,  by  referring  to  which  it  will  be  seen  that 
the  digestibility  of  soja  bean  ensilage  corresponds  closely  to  that 
of  clover  hay,  being  somewhat  lower  for  dry  matter  and  fiber,  but 
slightly  higher  for  protein,  fat,  and  carbohydrate  extract.  Table 
17  also  shows  that  the  digestibility  of  soja  bean  ensilage  is  con- 
siderably lower  than  that  of  cow  pea  ensilage.  It  was  found  in 
conducting  the  experiments  that  the  ensilage  from  soja  beans  was 
eaten  by  the  steers  much  less  readily  than  that  from  cow  peas ; 
and  the  data  given  show  that  smaller  amounts  of  dry  matter  of  the 
soja  beans  were  eaten. 

DIGESTIBILITY  OF  CORN-FODDER. 

By  corn-fodder  is  meant  the  entire  corn  plant  as  cut,  the  ears 
not  having  been  removed.  That  used  in  these  experiments  was 
a  good  quality  of  corn-fodder.  On  being  put  into  the  barn  it  had 
been  run  through  a  machine  by  which  it  was  cut  into  short  pieces, 
but  not  shredded.  Thus  it  consisted  of  short  pieces  of  stalk 
together  with  the  light  leaves  and  husks,  heavy  short  pieces  of  ears 
of  corn  and  some  shelled  corn.  It  was  exceedingly  difficult  to 
obtain  portions  for  feeding  and  for  analysis  which  would  represent 
even  a  close  approximation  to  uniformity.  Much  care  was  taken, 
however,  to  obtain  results  which  should  be  as  nearly  exact  as 
possible  with  the  methods  employed,  and  the  amount  of  error 
which  may  have  been  introduced  by  imperfect  sampling  will  be 
shown  later. 

As  might  be  expected,  the  corn-fodder  was  not  eaten  by  the 
steers  as  freely  as  the  corn  ensilage  had  been.  Of  course,  this 
would  be  the  case  with  the  fresh  substance,  but  it  was  also  found 
that  on  the  basis  of  dry  matter  a  smaller  amount  of  corn-fodder 
than  of  corn  ensilage  was  eaten.  This  fact  was  especially  notice- 
able with  Steer  No.  53. 


196 


BULLETIN   NO.   43. 


\April, 


The  data  and  the  results  obtained  in  the  experiments  with 
corn-fodder  are  given  in  Tables  10  and  n,  and  Table  12  gives  for 
comparison  the  results  of  all  determinations  made  in  the  United 
States. 

TABLE  10.  NUMBER  OF  POUNDS  (BOTH  FRESH  AND  DRY)  OF  CORN-FODDER  FED,  OF 
REFUSE,  AND  OF  DUNG,  FOR  EACH  STEKR;  AND  ALSO  THE  PERCENTAGE  COMPOSI- 
TION OF  THE  DRY  MATTER. 


Date. 

Amounts, 
pounds. 

Composition  of  dry  matter, 
percentages. 

1895. 

Fresh 
sub- 
stance. 

Dry 

matter 

Ash. 

Pro- 
tein. 

Fat. 

Fiber. 

Car- 
bohy- 
drate 
extract 

Steer  No. 


Feed  
Feed  

Mar.  22-23  .  . 
Mar.  24—25  .  . 

27.00 

12  .OO 

22.503 
Q.QQ2 

4.92 

A.  77 

6.99 
7.28 

1.91 

2  l8 

23.09 

21  1Q 

63.09 

64.  78 

Feed  

Mar.  26—27  •  • 

24.OO 

2O  .  804 

i   ^6 

6.76 

2.  02 

2^.77 

Refuse  
Refuse  

Mar.  22-23  .  . 
Mar.  24—27  .  . 

10.  19 

4.7C 

8.524 
T.Q7S 

5-30 

4.  77 

5  -06 
463 

.98 
I  OO 

32-37 
•J7  80 

56.29 

£C  7T 

Dung  
Dung  

Mar.  23-24.  . 
Mar.  25-28  .  . 

23-75 
53-91 

4.426 
9.418 

8.86 
10.45 

13.86 
12.68 

1.71 

i-45 

16.80 
20.15 

53.77 
55-27 

Steer  No.  54. 


Feed  
Feed  

Mar.  22-23  .  . 
Mar.  '24-25  .  . 
Mar.  26-27  .  . 

44-00 

32.00 
30.00 

36  .  669 
26.644 
26.005 

4-92 
4-37 
4-36 

6.99 

7.28 
6.76 

1.91 

2.18 

2.02 

23.09 
21.39 

23-77 

63.09 
64.78 
63.09 

Feed        

Refuse  .              

Mar.  22-23  •  • 
Mar.  24-27  .  . 

11.78 
10.31 

7.921 

8.463 

4.28 

3-55 

4-5i 
3-6? 

•93 

.68 

34-75 

34.87 

55-53 
57-23 

Refuse  .    

Dung  
Dung  

Mar.  23-24  .  . 
Mar.  25-28.  . 

53-72 
88.15 

11.523 
18.986 

8.32 
9-29 

12-55 
12.84 

2-35 
1.69 

15-36 
16.10 

61.42 

60.08 

Steer,  Roan. 


Feed  
Feed  
Feed  

Mar.  22-23  •  • 
Mar.  24-25.  . 
Mar.  26-27  .  . 

43.00 
33-00 
28  oo 

35.838 
27.477 
24.271 

4.92 

4-37 
4-36 

6-99 

7.28 
6.76 

1.91 
2.18 

2.02 

23.09 
21.39 
23.77 

63-09 
64.78 
63.09 

Refuse  

Mar.  22-23  .  . 
Mar.  24-27  .  . 

9-32 

8.28 

7.563 
6.973 

4.40 
4.27 

4-39 
4-32 

.92 
I.OI 

34.16 
34.98 

56.13 
55-42 

Refuse  

Dung  
Dunsr  .  . 

Mar.  23-24  .  . 
Mar.  2^-28.  . 

61.38 
0.1.60 

12.219 

IQ.  IQI 

9-05 

Q.  41 

11.68      1.45 

11.22        I    18 

18  49 

18.18 

59-33 
^0.81 

Steer  No. 


Feed  
Feed  
Feed    

Mar.  22-23  •  • 
Mar.  24-25  .  . 
Mar.  26-27  .  . 

46.00 
38.00 
37-oo 

38.338 

31-639 
32.073 

4.92 
4-37 
4-36 

6.99 

7.28 
6.76 

1.91 
2.18 

2.02 

23-09 

21.39 
23  77 

63.09 

6-1-78 
63.09 

Refuse  

Mar.  22-23.  • 
Mar.  24-27  .  . 

9.78 
12.66 

7.841 
10.224 

3-19 
2  94 

3-46 
3-36 

.72 
.69 

35-18 
36.  16 

57-45 

56.85 

55.16 
56.41 

Refuse  

Dung  

Dun£f 

Mar.  23-24.  . 
Mar.  25-28.  . 

62.44 
110.45 

10.463 
I9-I34 

H-73 
11.17 

13-49 
12.48 

i.  63 
1.65 

17.94 
18.29 

1896.] 


DIGESTION   EXPERIMENTS. 


197 


TABLE  n.  NUMBER  OF  POUNDS  OK  EACH  NUTRIENT  IN  THE  CORN-FODDER  FED,  IN 
THE  REFUSE  AND  IN  THE  DUNG,  DURING  A  PERIOD  OF  six  DAYS  ;  AND  ALSO  THE 
DIGESTION  COEFFICIENTS. 


Dry 

matter. 

Ash. 

Protein. 

Fat. 

Fiber. 

Carbo- 
hydrate 
extract. 

Steer  No. 


Corn-fodder  fed  

53.  2QQ 

2.452 

3.  7O6 

i  .067 

I2.27Q 

-3T  .7Qi; 

Amounts  refused  

12.  502 

.642 

.615 

.  12^ 

4.  IO7 

7  .OI"? 

Amounts  eaten  

40.797 

i  .810 

3.OQI 

.044 

8.172 

26.78O 

Dung  excreted  

13.  844 

i  .  17& 

1.807 

.21^ 

2.641 

7.8O7 

Amounts  digested  

26.953 

.4-1.4. 

1.284 

.711 

C  .  C-2I 

i  8  .07^ 

Per  cent,  digested  .  .  . 

66.07 

23.98 

41.54 

77.44 

67.68 

70.85 

Steer  No. 


Corn-fodder  fed  

80.318 

A.  101 

6.260 

i  806 

2O.  ^40 

56  800 

Amounts  refused    

16.384 

640 

668 

141 

57O4 

92-ir 

Amounts  eaten  

72    Q^4 

•2  1  61? 

e    £Q2 

I    67=1 

TJ.    6.1  C 

47    mo 

Dung  excreted  

^o.  SOQ 

27.23 

3.887 

.KQ2 

4.827 

18  480 

Amounts  digested  

42.  J.2^ 

.740 

I   .70=1 

I.O83 

9.8l8 

2Q.O7Q 

Per  cent,  digested  .  .  . 

58.17 

21.37 

30.49 

64.66 

67.04 

61.16 

Steer  Roan, 


Corn-fodder  fed  .  .  . 

87.1586 

4.022 

6.  145 

I  .  ~1T\ 

IO.Q22 

cc  .72J. 

Amounts  refused  

14.  536 

.631 

.6l3 

.I4O 

K  .02^ 

8.  ICQ 

Amounts  eaten  

73.O"io 

3.  1QI 

5-512 

i  .6n 

I4.8OQ 

47  ,6m 

Dung  excreted  

31.410 

2  .Oil 

3.580 

.441 

C  .7J.Q 

18.725 

Amounts  digested  

41.640 

.478 

1.932 

1  .190 

9.150 

28.890 

Per  cent,  digested  .  .  . 

57.00 

14.10 

35.05 

72.87 

61.41 

60.67 

Steer  No.  57. 


Corn-fodder  fed  

102.050 

4.668 

7.151 

2    070 

27.244 

64.017 

Amounts  refused  

18.065 

.551 

.615 

.  127 

6.4^7 

10.315 

Amounts  eaten  

83.985 

4.  1  17 

6.  5^6 

1  .041 

16  787 

CJ..6O2 

Dung  excreted   

2Q.  ^07 

<\    -26  ^ 

3  800 

.4Q1 

5    ^78 

16  561 

Amounts  digested  

ci.<288 

7^2 

2  .  7l6 

I  .4^0 

1  1     J.OO 

l3  .O4I 

Per  cent,  digested.  .  .  . 

64.76 

18.27 

41.86 

74.63 

67.96 

69.67 

198 


BULLETIN   NO.   43. 


\  April, 


TABLE    12.      DIGESTIBILITY    OF    CORN-FODDER    BY    CATTLE,  AS    SHOWN   BY    ALL 
EXPERIMENTS  MADE  IN  THE  UNITED  STATES. 


Experiments  made    by 

Trial 
No. 

Animals 
employed. 

Dry 
matter 

Ash. 

Pro- 
tein. 

Fat. 

Fiber. 

Car- 
bohy- 
drate 
ex- 
tract. 

Pennsylvania   

I 

2 

Steer  No.  I  .  . 
Steer  No.  2  .  . 

67-1 
67.7 

32.3 
42.9 

55-7 
6l.5 

76.8 
81.6 

76.0 
72.9 

66.5 
67.2 

Pennsylvania  

Pennsylvania  

3 
4 

Steer  No.  I  .  . 
Steer  No.  2  .  . 

68.8 
64.2 

51-0 
46.8 

46.6 
40.7 

8o.O 

78.7 

73-1 
69-3 

70-3 
65.0 

S 
6 

Steer  No.  I  .  . 
Steer  No.  2  .  . 

63-9 
57-6 

25.6 
9.9 

36.0 
22.4 

84.2 
65-7 

74-3 
66.7 

65.6 
59-9 

Pennsylvania  

Average  of  six  determinations  

64.9 

34.7 

43.8 

77.8 

72.1 

65.8 

'Wisconsin    

i 

2 

Cow  No.  I  .  . 
Cow  No.  2  ... 

58.8 
60.9 

14-9 
23.2 

46.4 
51.2 

66.7 
70.4 

53-4 

58-9 

64.0 
66.0 

Wisconsin  

Average  of  two  determinations  

59.9 

19.1 

48.8 

~4i-5 
30-5 
35-1 
41.9 

68.6 

56.2 

65.0 

Illinois  

I 
2 

3 
4 

Steer  No.  53. 
Steer  No.  54. 
Steer  Roan  .  . 
Steer  No.  57  . 

66.1 
57-2 
58.0 
64.8 

24.0 
21.4 
14.1 

18.3 

77-4 
64.7 
72-9 
74.6 

67.7 
67.0 
61.4 

68.0 

70.9 
61.2 
60.7 
69.7 

Illinois  

Average  of  four  determinations  

61.5 

19.4 

37.2 

72.4 

66.0 

65.6 

Average  of  twelve  determinations  

62.9 

27.0 

42.4 

74.5 

67.4 

65.7 

Although  the  average  of  our  results  from  the  experiments 
with  corn-fodder  agrees  well  with  the  general  average  of  all  Amer- 
ican experiments,  and  the  individual  variations  are  no  wider  than 
are  commonly  reported  from  digestion  experiments,  yet  they  are 
not  satisfactory,  because  they  are  not  more  nearly  exact;  and  the 
evidence  of  our  other  digestion  experiments  proves  that  the 
digestibility  of  foods  can  be  determined  with  a  much  higher  degree 
of  accuracy  than  is  shown  by  the  results  from  corn-fodder. 

A  careful  attempt  has  been  made  to  locate  the  source  of  error 
in  these  experiments.  As  already  mentioned,  it  was  extremely 
difficult  to  obtain  fair  samples  of  the  corn-fodder.  This  difficulty 
was  anticipated,  and  in  order  to  determine  the  influence  of  an 
error  which  might  be  introduced  from  that  source  a  check  sample 
was  taken  of  every  portion  of  feed,  refuse,  and  dung  sampled  for 
analysis.  Then  the  percentage  of  total  dry  matter  in  these  check 
samples  was  determined.  This  furnishes  data  for  a  second  deter- 
mination of  the  digestibility  of  the  dry  matter  entirely  independent 
of  the  samples  and  analyses  of  the  former  determination.  For 
comparison  both  determinations  are  given  below: 

TABLE  13.     DIGESTION  COEFFICIENTS  FOR  DRY  MA.TTER  OF  CORN-FODDER. 


Steer 
No.  53. 

Steer 
No.  54. 

Steer 
Roan. 

Steer 
No.  57. 

Average. 

First  determination  

66   i 

IS    2 

^7    O 

64  8 

6l.5 

Second  determination  

66.2 

CQ.O 

58.4 

65.2 

62.2 

Total  variation  .  . 

.  i 

.8 

I.  -I 

.4 

.7 

1896.] 


DIGESTION   EXPERIMENTS. 


199 


This  shows  a  maximum  variation  of  1.4  per  cent,  with  Roan, 
and  a  minimum  of  .1  per  cent,  with  No.  53.  The  average  variation 
is  .7  per  cent.  Certainly  the  error  due  to  imperfect  sampling  is 
very  small  and  does  not  account  for  the  variation  of  nearly  10  per 
cent,  between  different  animals. 

It  has  already  been  pointed  out  that  irregularities  in  voiding 
the  dung  might  introduce  an  error  in  the  result.  In  order  to 
determine  the  possible  influence  of  such  an  error  the  digestion 
coefficients  were  determined  for  a  period  of  four  days'  feeding  as 
well  as  for  the  full  period  of  six  days.  Both  determinations  are 
given  below: 

TABLE  14.     DIGESTION  COEFFICIENTS  FOR   DRY  MATTER  OF  CORN-FODDER. 


Steer 
No.  53. 

Steer 
No.  54. 

Steer 
Roan. 

Steer 

No.  57. 

Average. 

From  six  days'  period  

66.1 

«;8.2 

C,7    o 

64  8 

61   e. 

From  four  days'  period  .... 

64..  Q 

C.7.O 

1:7  .  T 

6/1    2 

60  8 

Total  variation  

1.2 

I    2 

.  i 

.6 

7 

It  is  well  understood  that  four  days'  time  is  too  short  a  period 
to  be  relied  upon  in  determining  digestion  coefficients,  but  even 
by  using  the  data  obtained  in  four  days  we  have  only  an  average 
variation  of  .7  per  cent,  with  a  maximum  of  1.2  per  cent,  from  the 
coefficients  for  dry  matter  obtained  in  the  six  days'  period.  Evi- 
dently the  wide  variation  between  the  animals  is  not  due  to  irregu- 
larities in  voiding  the  dung. 

There  seems  to  be  no  alternative  but  to  conclude  that  the 
variations  are  due  to  the  individuality  of  the  animals  themselves. 
By  taking  a  general  view  of  the  results  obtained  from  all  the  ex- 
periments, including  those  with  corn  ensilage,  cow  pea  ensilage, 
soja  bean  ensilage,  and  corn-fodder,  this  animal  individuality  be- 
comes more  evident.  The  following  table  gives  for  comparison 
the  digestibilty  of  the  dry  matter  of  each  of  the  four  food-stuffs: 

TABLE  15.     DIGESTION  COEFFICIENTS   FOR  TOTAL  DRY   MATTER,  SHOWING  ANIMAL 

INDIVIDUALITY. 


Food-stuff. 

Steer 
No.  53. 

Steer 

No.  54. 

Steer 
Roan. 

Steer 

No.  57. 

Average. 

Corn  ensilage  

61.7 

61  .9 

cq  8 

63.  t; 

61  7 

Cow  pea  ensilage  

^Q.Q 

Co    c 

CQ     O 

60  i 

CQ    5 

Soja  bean  ensilage  

4Q.8 

4Q    8 

4Q   4. 

CQ    T 

4Q    8 

Corn-fodder  

66  i 

58    2 

C7    o 

64.8 

61   * 

The  result  obtained  from  Steer  No.  53  with  corn-fodder  should 
be  omitted  in  the  comparison,  owing  to  the  fact  that  he  ate  only 


200  BULLETIN   NO.   43.  [April, 

about  one-half  as  much  of  that  food  as  the  other  animals,  as  may 
be  seen  from  Table  10.  It  is  highly  probable  that  the  effect  of 
eating  such  a  small  amount  of  food  would  be  easily  to  destroy  the 
animal  individuality  in  that  case.  This  single  result  being  disre- 
garded it  will  be  seen  that  No.  53  and  No.  54  gave  results  which 
are  markedly  uniform,  that  in  every  case  Roan  gave  the  lowest  re- 
sult and  No.  57  the  highest. 

There  are  two  possible  sources  of  this  animal  individuality — 
first,  in  the  process  of  mastication  ;  and,  second,  in  the  action  of 
the  digestive  fluids.  That  it  is  at  least  chiefly  due  to  the  first  of 
these  sources  seems  evident  from  a  further  study  of  Table  15. 
With  those  foods  which  would  seem  to  require  the  least  effort  in 
mastication,  as  cow  pea  ensilage  and  soja  bean  ensilage,  the  indi- 
viduality is  the  least  marked,  but  it  becomes  more  apparent  with 
the  corn  ensilage,  which  contains  the  whole  kernels  of  corn,  and 
it  is  most  prominent  with  the  corn-fodder,  which  contains  the 
whole  kernels  in  a  dry  and  hard  condition.  This  view  of  the 
source  of  this  animal  individuality  is  strengthened  by  the  fact  that 
kernels  of  corn  which  escape  mastication,  pass  through  the  ali- 
mentary canal,  and  are  excreted  with  the  dung  have  practically 
the  same  composition  before  and  after  passing  through  the  animal, 
indicating  that  if  the  kernels  are  not  ground  or  broken  the  digest- 
ive fluids  have  little  or  no  action  upon  them.  By  referring  to  the 
results  obtained,  as  given  in  Table  12,  we  see  that  the  low  digesti- 
bility of  the  dry  matter  of  corn-fodder  as  determined  by  Steers 
No.  54  and  Roan  is  mainly  found  in  the  protein  and  carbohydrate 
extract,  and  then  by  turning  to  Table  16  it  will  be  seen  that  these 
two  substances  constitute  more  than  90  per  cent,  of  the  total  dry 
matter  of  shelled  corn,  but  less  than  60  per  cent,  of  dry  corn  stover. 

This  subject  is  receiving  further  consideration. 

METABOLIC  PRODUCTS. 

By  metabolic  products  is  meant  those  animal  products  result- 
ing from  the  use,  wear,  or  waste  of  the  animal  tissues  or  fluids. 
Some  of  these  products,  coming  from  the  wear  of  the  alimentary 
canal,  from  the  digestive  fluids,  etc.,  are  thrown  off  with  the  dung. 
Attempts  have  been  made  by  different  German  and  American 
experimenters  to  determine  the  amount  of  some  of  these  metabolic 
products  contained  in  the  dung,  but  the  results  so  far  obtained  are 
neither  concordant  nor  conclusive.  When  our  knowledge  con- 
cerning these  products  shall  have  become  exact  and  trustworthy, 
it  is  probable  that  the  amount  of  these  metabolic  products  will  be 
subtracted  from  the  amount  of  dung  in  order  to  determine  the 


1896.]  DIGESTION   EXPERIMENTS.  2OI 

exact  amount  that  is  truly  indigestible  food,  although  in  calculat- 
ing only  the  comparative  value  of  foods  it  may  never  be  neces- 
sary. 

It  may  be  stated  that  one  who  is  familiar  with  the  work  of 
Stutzer,  Pfeiffer,  Prof.  Jordan,  Dr.  Gustav  Kiihn,  and  others, 
along  the  lines  of  metabolic  products  and  natural  and  artificial 
digestion,  is  forced  to  the  conclusion  that  our  present  knowledge 
does  not  enable  us  to  apply  corrections  to  animal  digestion  for 
metabolic  products  with  any  satisfactory  degree  of  assurance  of 
accuracy. 

SUMMARY. 

The  composition  of  cow  pea  ensilage  corresponds  very  closely 
to  that  of  clover  hay,  the  most  important  difference  being  in  the 
higher  percentage  of  fat  found  in  the  clover,  but  the  digestibility 
of  the  cow  pea  ensilage  is  so  much  greater  that  it  furnishes  an 
equal  amount  of  fat  and  much  more  protein  and  total  energy  than 
the  clover  hay. 

Soja  bean  ensilage  resembles  clover  hay  both  in  composition 
and  digestibility.  It  furnishes  an  equal  amount  of  protein,  more 
fat,  but  less  total  energy  than  clover  hay. 

Both  of  these  leguminous  forage  plants  draw  upon  the  free 
nitrogen  of  the  air  in  an  indirect  way  for  a  part  of  their  food  supply; 
their  composition  shows  a  high  percentage  of  nitrogen  ;  and  they 
have  great  value  for  improving  the  soil. 

Corn-fodder  and  corn  ensilage  have  about  the  same  digesti- 
bility for  total  dry  matter  and  furnish  nearly  equal  amounts  of 
energy.  The  fodder  furnishes  more  digestible  carbohydrate 
extract,  but  the  ensilage  slightly  more  of  the  other  nutrients. 

As  compared  with  cow  peas  and  soja  beans,  the  corn-fodder 
and  corn  ensilage  have  a  much  higher  value  for  energy  or  fat  pro- 
duction, but  the  cow  pea  ensilage  and  soja  bean  ensilage  are  far 
more  valuable  for  animal  growth  or  the  production  of  milk. 

CYRIL  G.  HOPKINS,  M.  S.,  Chemist. 


202  BULLETIN   NO.    43.  \April, 

APPENDIX. 


CONSTITUENTS  AND  USES  OF  FOOD. 

The  value  of  palatable  food  depends  largely  upon  two  things — its  composition  and 
its  digestibility.  The  composition  is  determined  by  chemical  analysis,  which  shows  the 
different  substances  the  food  contains,  and  also  the  amount,  or  per  cent.,  of  each  sub- 
stance. By  the  digestibility  we  mean  the  per  cent,  digested  of  the  food  which  is  eaten 
by  the  animal,  and  not  only  the  per  cent,  of  the  total  food  eaten  but  also  the  per  cent. 
of  each  substance  or  group  of  substances  which  the  food  contains.  The  digestibility  of 
food  is  determined  by  actual  trial  with  animals. 

COMPOSITION  OF  FOODS. 

Most  plants  are  composed  of  thirteen  simple,  primary  substances  which  are  called 
elements.  An  element  is  a  substance  which  cannot  be  divided  by  any  known  means  into 
two  different  substances.  Iron  is  an  element,  because  pure  iron  contains  nothing  but 
iron,  and  it  cannot  be  separated  into  anything  but  iron.  Sulfur  and  carbon  are  also 
elements.  Some  elements  exist  in  the  form  of  gas  ;  such  are  the  elements  oxygen  and 
nitrogen,  of  which  the  air  is  chiefly  composed. 

A  compound  is  composed  of  two  or  more  elements  which  are  united  in  such  a  way 
that  the  elements  themselves  are  not  easily  recognized.  Water  is  a  compound  of  the 
two  elements  oxygen  and  hydrogen,  both  of  which  are  gases;  and  sugar  is  a  compound  of 
these  two  elements  and  the  element  carbon.  If  sugar  is  heated  the  elements  oxygen  and 
hydrogen  are  driven  off,  mainly  in  the  form  of  water,  or  steam,  and  only  the  black  car- 
bon remains.  If  the  heat  is  continued  this  carbon,  or  charcoal,  may  unite  with  the  ele- 
ment oxygen  of  the  air  and  form  the  compound  carbon  dioxid,  which  is  a  gas-. 

The  name  of  any  simple  compound  will  usually  show  just  what  elements  the  com- 
pound contains.  Iron  sulfid  is  a  compound  of  iron  and  sulfur.  Iron  oxid  contains  iron 
and  oxygen;  carbon  dioxid  (^/z  meaning  two)  contains  carbon  and  oxygen;  carbon  disulfid, 
carbon  and  sulfur ;  and  sodium  chlorid  (common  salt)  is  composed  of  the  elements 
sodium  and  chlorin. 

There  are  four  of  the  thirteen  elements  of  which  plants  are  composed  that  are  of 
especial  importance : 

1.  Carbon.     This  solid  element  is  well  represented  by  soot  or  lamp  black.    Ordinary 
charcoal  is  chiefly  carbon  ;  and  charcoal  made  from  pure  sugar  or  starch  is  pure  carbon. 
Coal  is  also  mainly  carbon.     All  kinds  of  carbonates,  of  course,  contain  carbon. 

2.  Hydrogen.     This  element  is  a  gas  when  not  combined  with  other  elements.     It 
is  the  lightest  of  all  known  substances.     When  hydrogen  burns  it  unites  with  the  oxygen 
of  the  air  and  forms  the  compound  which  we  call  water. 

3.  Oxygen.     About  one-fifth  of  the  air  consists  of  oxygen  in  the  free,  or  uncombined, 
state;  and   eight-ninths  of  water  is  oxygen.     Generally    compounds    whose   scientific 
names  end  in  -ate  contain  oxygen,  and  all  oxids  contain  oxygen. 

4.  Nitrogen.     This  element  constitutes  about  four-fifths  of  the  air.     It  is  contained 
in  all  kinds  of  nitrates,  as  potassium  nitrate  (saltpeter).     Ammonia  is  a  compound  of 
nitrogen  and  hydrogen.  Nitrogen  is  one  of  the  valuable  elements  of  commercial  fertilizers. 

These  four  elements,  carbon,  hydrogen,  oxygen,  and  nitrogen,  constitute  what  is 
called  organic  matter.  All  that  plants  contain  besides  this  organic  matter  and  water  is 
what  remains  as  ash  when  the  plants  are  burned. 

It  should  be  noted  that  in  the  higher  forms  of  life  there  is  an  important  difference 
between  plants  and  animals  in  regard  to  the  sources  of  their  food  materials.  The  plant 


1896.]  DIGESTION   EXPERIMENTS.  2O3 

for  its  supplies  draws  upon  the  elements,  usually  in  the  form  of  very  simple  compounds, 
such  as  water,  carbon  dioxid,  ammonia,  etc.  The  plant  takes  these  elements  and  with 
the  aid  of  the  sun's  energy  builds  up,  or  manufactures,  of  them  very  complex  organic 
substances,  as  sugar  and  starch.  Some  of  this  organic  matter  which  the  plant  has 
manufactured  is  used  as  food  by  the  plant  itself  for  the  purpose  of  carrying  on  its  own 
vital  processes,  and  in  thus  furnishing  energy  for  the  life  and  work  of  the  plant  this  com- 
plex matter  is  reduced  to  carbon  dioxid,  water,  etc.,  and  in  these  simple  forms  is  thrown 
off  by  plant  respiration  ;  but  the  rest  of  this  manufactured  organic  matter  is  in  part  con- 
verted into  the  plant  tissues  and  in  part  stored  up  in  the  plant  either  for  its  own  subse- 
quent use  or  for  other  purposes. 

The  animal,  on  the  other  hand,  must  depend  for  its  energy  on  food  alone.  It  has  no 
power  to  manufacture  its  own  food  from  elementary  substances,  but  must  have  the 
ready-formed,  complex  organic  matter.  Some  of  this  is  transformed  by  the  animal  into 
its  own  body,  but  by  far  the  larger  part  is  burned  in  the  body  to  furnish  force  and  heat, 
and  is  then  thrown  off  in  the  simple  forms  of  carbon  dioxid,  water,  etc-.  In  a  study  of 
food  for  animals  it  is  of  chief  importance  to  learn  how  much  and  what  kinds  of  these 
organic  compounds  the  food  contains. 

Foods  are  separated  by  analysis  into  the  six  different  substances  or  groups  of  sub- 
stances which  are  numbered  below  : 

1.  Water.     In  grain  or  hay  which  seems  very  dry  there  is  still  a  considerable  amount 
of  water,  or  moisture,  usually  not  less  than  10  per  cent.     In  ensilage,  in  green  fodders, 
and  in  root  crops  the  amount  of  water  is  very  much  more,  usually  from  70  to  90  per  cent. 
After  the  water  is  removed  from  a  food,  all  that  remains  is  called  dry  matter. 

2.  Ash.     By  the  term  ash  is  meant  the  mineral  matter  which  remains  when  the  dry 
matter   is  burned.     The    ash  consists  of  such  compounds    as  sodium  chlorid   (common 
salt),  potassium    carbonate    (contained    in   lye  from   wood  ashes),    magnesium   sulfate 
(Epsom  salts),  calcium  phosphate  (''lime  phosphate"),  silicon  dioxid  (sand),  and  iron 
oxid. 

That  part  of  the  dry  matter  which  passes  off  in  burning  is  called  organic  matter. 
This  contains  only  the  four  elements,  nitrogen,  carbon,  hydrogen,  and  oxygen;  but 
these  are  united  in  many  different  complex  compounds.  These  constitute  by  far  the 
largest  and  most  valuable  part  of  food.  This  organic  matter  is  separated  by  analysis 
into  four  classes  : 

3.  Protein.     All  of  the  organic  compounds  which  contain  nitrogen  are  called  protein 
(carbon,  hydrogen,  and  oxygen  are  also  present  in  protein).     The  gluten  of  wheat  flour 
is  one  kind  of  protein. 

4.  Fat.     This  substance  is  composed  of  carbon  and  hydrogen  with  a  small  amount 
of  oxygen.     It   consists    mainly  of  the  various  oils   and  fats    contained  in  plants,  some 
examples  of  which  are  cotton-seed  oil,  linseed   oil,  corn  oil,  etc.     After  subtracting  the 
protein  and  the   fat  from   the  organic  matter  the  remainder  is  called  carbohydrates.     A 
carbohydrate  is  composed  of  carbon,  hydrogen,  and  oxygen,  the  last  two  elements  being 
present  in  the  same  ratio  to  each  other  as  they  are  in  water.     In  analysis  carbohydrates 
are  separated  into  two  classes  : 

5.  Fiber.     The  woody  structure,  or  frame-work,  of  plants  is  called  fiber.     The  fiber 
of  flax  and  that  of  hemp  are  familiar  examples.     Paper  is  largely  made  from  woody  fiber. 

6.  Carbohydrate  extract.     This  substance  consists  of  the  more  easily  soluble  carbo- 
hydrates, sugar,  starch,  etc.,  which  are  separated  from  the  fiber  by  extraction  with  acid 
and  alkaline  solutions.     (These  extracted  carbohydrates  are  often  called  by  the  indefinite 
term  nitrogen-free  extract.~) 

In  the  following  table  is  given  the  average  composition  of  a  number  of  American 
food-stuffs  of  importance  to  Illinois  agriculturists.  (The  compilation  of  Jenkins  and 
Winton  and  analyses  by  the  Minnesota,  North  Carolina,  and  Illinois  experiment  stations 
have  been  used  in  making  these  averages.) 


204 


BULLETIN    NO.   43. 


\April, 


The  composition  of  all  the  food-stuffs  is  given  on  the  basis  of  100  parts  of  dry  matter 
in  order  that  they  may  be  comparable,  the  amount  of  water  being  so  variable  with  changes 
of  weather  etc.,  that  a  fair  comparison  cannot  be  made  on  the  basis  of  fresh  substance. 

The  first  column  shows  the  total  number  of  analyses  of  which  the  average  is  given. 
The  second  column  shows  the  amount  of  food  required  for  100  parts  of  dry  matter,  the 
difference  being  water,  as  shown  in  the  next  column.  The  remaining  columns  show  the 
percentage  composition  of  the  dry  matter. 

TABLE  16.     AVERAGE  COMPOSITION  OF  SOME  AMERICAN  FOOD-STUFFS. 


Food-stuffs. 

No.  of 
com- 
plete 
anal- 
yses. 

Composition  of  food-stuffs  per  100  parts  of 
dry  matter. 

Total 
fresh 
sub- 
stance . 

Water. 

Ash. 

Pro- 
tein. 

Fat. 

Fiber. 

Car- 
bohy- 
drate 
extract 

*Corn-fodder  (field  cured)  .  . 
*Corn  stover  (field  cured).  . 
Clover  hay     

35 
60 
38 
68 

12 

173.0 
166.9 
118.1 
115.2 
no.  i 

73-o 
66.9 
iS.i 
15-2 

IO.I 

4-7 

5-7 
7-3 
5-i 
5-6 

7-8 
6.4 

14-5 
6.8 

4-4 

2.8 

i-7 
3-9 

2-9 

2-5 

24-7 
33-0 
29.1 

33-5 
40.7 

6o.O 

53-2 
45-2 
51-7 
46.8 

Timothy  hay  

Oat  straw  

Corn  ensilage      .  .  . 

IO2 

5 
4 
4 

472.0 

357-1 
360.0 
405-0 

372-0 

257-1 
260.0 
305.0 

6.6 
9-3 

IO.O 

13-5 

8.1 
14-9 
14-3 
13.6 

3-8 
4.1 
2.9 
4-5 

28.5 
29.9 
27.0 
32.7 

53-o 

41.7 
45-8 
35.7 

Clover  ensilage     

Cow  pea  ensilage  

Soja  bean  ensilage  . 

Corn  .  *  

86 
30 
10 
310 

111.9 
112.4 

112.  2 
.111-7 

11.9 
12.4 

12.2 
II-7 

i-7 
3-4 
2.7 

2.O 

ii.  5 
13.2 

13-9 
13-3 

5-6 

5-6 

2.0 

2-3 

2.6 

10.8 
3-0 

2.0 

78.6 
67.0 

78.4 
80.4 

Oats  

Barley  .          .        

Wheat     .  .            

\Vheat  bran    

88 
32 
35 

H3-5 

110.6 
108.9 

13-5 

10.6 

8.9 

6.6 

.8 
7-8 

17.4 

32-5 
46.1 

4-5 
7-0 
14.2 

IO.2 

1.8 
6.1 

61.  3 

57-9 
25-8 

Gluten  meal  

Cotton  seed  meal  

*  By  corn-fodder  is  meant  the  whole  plant  as  cut;  what  is  left  after  the  ears  are  removed  is  called 
corn  stover. 

THE  DIGESTIBILITY  OF  FOODS. 

When  food  is  taken  into  the  stomach,  it  is,  in  one  sense,  not  yet  in  the  system  of  the 
animal;  but  it  is  in  a  tube  which  runs  through  the  body.  This  tube  is  called  the  ali- 
mentary canal.  It  consists  of  the  mouth,  throat,  stomach,  small  intestines,  and  large 
intestines.  When  food  is  taken  into  this  alimentary  canal  it  is  acted  upon  and  partly 
dissolved  by  certain  liquid  agents,  as  the  saliva  in  the  mouth,  the  gastric  juice  in  the 
stomach,  and  other  liquids  in  the  intestines.  That  part  of  the  food  which  is  dissolved  is 
said  to  be  digested.  It  passes  through  the  walls  of  the  alimentary  canal  and  into  the 
true  system  of  the  animal.  It  enters  the  circulation  and  may  be  carried  to  any  part  of 
the  animal  body.  But  that  part  of  the  food  which  cannot  be  dissolved  by  these  digestive 
fluids  is  indigestible.  It  passes  on  through  the  alimentary  canal  and  is  excreted  as  dung. 

It  is,  of  course,  only  the  digestible  portion  of  the  food  that  is  of  value  for  energy  and 
the  formation  of  animal  products,  and  it  is  now  readily  understood  that  the  composition 
alone  does  not  determine  the  value  of  food,  but  rather  that  the  value  depends  both  upon 
the  composition  and  the  digestibility. 

There  are  very  important  differences  in  the  digestibility  of  different  foods,  and  also 
of  the  different  substances  in  the  same  food.  The  per  cent,  which  is  digestible  of  any 
substance  is  called  the  digestion  coefficient  of  that  substance.  For  example,  if  cattle 
digest  63  per  cent,  of  the  total  dry  matter  of  corn-fodder,  then  63  is  the  digestion  coefficient 
of  the  dry  matter.  Seventy-four  is  the  digestion  coefficient  of  the  fat  in  corn-fodder 
because  74  per  cent,  of  the  total  amount  of  fat  is  digestible. 

Table  17  shows  the  digestion  coefficients  of  a  number  of  important  food-stuffs. 


1896.] 


DIGESTION   EXPERIMENTS. 


205 


TABLE  17.     DIGESTIBILITY  OF  FOOD-STUFFS  AS  DETERMINED  BY  AMERICAN  DIGES- 
TION EXPERIMENTS. 


*Z 

0 

-•a, 

3   v> 

3  5' 
5.W 

.<"  <r 

rt 
X 

•* 

*1 

Digestion  Coefficients. 

Determinations  made 
by    experiment    sta- 
tions of  — 

a 

^ 

£• 

f? 
j< 

> 

VI 

3J 

£ 
2. 
r 

"J 
P 

*tj 

a1 
n> 
>i 

Carbohydrate 
extract. 

With  cattle  — 

12 
4 
17 
4 
4 

63 
62 
64 
60 
50 

27 

45 
32 
30 
28 

42 
52 
49 

58 
55 

74 
52 
82 
63 
49 

67 
67 
63 

52 
43 

66 
64 
68 

73 
61 

Pa.,  W1S,  and  111. 
Pennsylvania. 
Pa.,  Wis.,N.  C.and  111. 
Illinois. 
Illinois. 

Corn  ensilage  

Sola  bean  ensilage   

With  sheep  — 

12 

7 
7 

2 

59 
53 
61 

87 

37 
37 

49 

52 
78 

87 

67 
48 
72 
88 

56 
47 
25 

33 

64 
60 
68 
9i 

Maine. 
Wis.  and  Maine. 
Maine  and  Mass. 
Maine. 

Clover  hay          

Wheat  bran  

Gluten  meal        

With  swine  — 
Corn  meal  

2 

I 

90 

83 

.... 

88 
69 

80 
46 

39 

38 

94 
89 

Maine  and  Minn. 
Maine. 

Corn  (shelled)   

Now,  by  knowing  the  composition  of  food  and  also  the  digestibility  of  the  different 
substances  which  the  food  contains,  we  are  able  to  determine  just  the  amount  of  each 
substance  that  is  digestible  by  the  animal.     This  is  shown  in  Table  18. 
TABLE  18.    AMOUNTS  OF  DIGESTIBLE  SUBSTANCES,  AS  DETERMINED   BY  COMPUTA- 
TION FROM  TABLES  16  AND  17. 


0 

3ounds  of  digestible  nutrients 

from  100  Ib.  of  dry 

*° 

matter. 

• 

*•<     rt 

n    3 

3  j: 

H 

JP, 

^ 

M 

iTl 

CLO 

S-  o 

£ 

| 

p 

5s 

3  2 

2.  "" 

n>  ._. 
iS 

p 

5' 

J1 

ST  g" 

Vg 

crZL 

£ 

era 

•    p- 

n 

^J 

With  cattle— 

173  o 

63 

1.3 

3-3 

2.1 

Tft    5 

39-6 

Iig.OOO 

167.0 

?      ft 

3-3 

.q 

22.1 

34  .0 

II4,OOO 

472.O 

64 

2.2 

4.0 

3.  1 

18.0 

36.0 

121  OOO 

360.0 

60 

3.O 

8  3 

T    R 

14.  0 

33-4 

III  OOO 

Soja  bean  ensilage  

405.0 

50 

3*8 

7-5 

2.2 

14.  1 

?T    8 

9O,OOO 

With  sheep  — 

Timothy  hay  

ITC-2 

CQ 

l.q 

3  3 

l.q 

TH  8 

33.  1 

III.OOO 

118.1 

CO 

2.7 

7    5 

I    Q 

13  7 

27    i 

98  ooo 

\Vheat   bran  

113.5 

61 

?  6 

41  .7 

121  OOO 

Gluten  meal   

no  6 

87 

28.3 

6.2 

6 

K2.7 

178  ooo 

With  swine  — 

117  6 

QO 

IO    I 

4.  S 

i  .0 

73    O 

177  ooo 

Corn  (shelled)  

111.9 

83 

7-9 

2.6 

I.O 

70.0 

158,000 

*  These  terms  are  explained  on  page  206.  It  should  be  noted  that  Table  16  gives  the  composition  of 
foods  from  a  large  number  of  averages ;  that  Table  17  gives  the  average  digestibility  from  a  much 
smaller  number  of  determinations;  that  Table  18  is  derived  from  Tables  16  and  17,  which  are  independent 
of  each  other;  and,  finally,  that  the  close  agreement  in  Table  18  between  the  total  dry  matter  and  the 
sum  of  its  constituents  is  indicative  of  the  general  accuracy  of  the  results. 


206  BULLETIN   NO.   43.  [April, 

THE  USES  OF  FOOD. 

The  primary  uses  of  food  are  (i)  to  form  animal  tissue,  as  muscle,  bone,  fat,  etc., 
and  (2)  to  supply  energy,  as  muscular  power,  heat,  etc. 

Food  may  be  converted  into  an  animal  product,  as  milk,  for  subsequent  use.  Fat 
is  sometimes  considered  as  a  product  which  is  simply  stored  by  the  animal  for  future  use, 
but  it  is  only  in  degree  that  fat  differs  in  this  respect  from  some  other  tissues  of  the  body. 

The  using  of  food  for  these  various  purposes  is  called  animal  nutrition,  and  each 
substance  in  the  food  which  the  animal  digests  and  uses  is  called  a  nutrient.  The 
analysis  of  food  shows  what  nutrients  it  contains,  and  the  uses  which  the  animal  makes 
of  these  different  nutrients  is  a  most  important  consideration. 

It  may  be  stated  that,  although  water  usually  constitutes  more  than  half  of  the 
animal  body,  the  water  which  is  contained  in  food  is  of  no  more  value  as  a  nutrient 
than  the  same  amount  of  water  from  the  well  or  spring. 

Ash,  or  mineral  matter,  contributes  largely  to  the  formation  and  repair  of  the 
skeleton.  It  is  usually  stated  that  most  food-stuffs  contain  such  an  abundant  supply 
of  ash  that  this  subject  needs  no  further  mention ;  but  that  the  subject  is  worthy  of 
careful  consideration  has  been  proved  by  such  experiments  as  Professor  Henry  reports 
from  the  Wisconsin  Experiment  Station  in  Bulletin  No.  25.  The  experiments  were 
made  with  a  large  number  of  pigs,  which  were  divided  into  three  groups.  The  pigs  of 
the  first  group  were  fed  corn  meal ;  those  of  the  second  group,  corn  meal  and  hard-wood 
ashes,  and  those  of  the  third  group  were  fed  corn  meal  and  bone  meal.  From  the  aver- 
age results  of  three  separate  trials,  Professor  Henry  draws  the  conclusion  that  the  effect 
of  the  bone  meal  and  ashes  was  to  save  about  130  Ib.  of  corn  in  producing  100  Ib.  of 
gain  in  the  live  weight  of  the  hogs  ;  and  he  recommends  that  either  hard-wood  ashes  or 
bone  meal  be  fed  with  corn. 

Protein  is  the  only  nutrient  of  the  food  which  contains  the  element  nitrogen. 
Something  of  the  importance  of  protein  in  the  food  may  be  understood  from  the  fact 
that  the  flesh,  or  lean  meat,  the  hide,  membranes,  ligaments,  tendons,  internal  organs, 
and,  in  fact,  all  working  parts  of  the  body,  excepting  the  bones,  are  composed  almost  en- 
tirely of  protein  ;  and  they  cannot  be  formed  from  anything  but  protein.  The  casein  of 
milk  is  protein  ;  and  the  albumen,  or  white,  of  eggs  is  a  very  pure  form  of  protein. 

For  the  highest  production  of  milk  or  eggs  or  animal  growth,  foods  rich  in  protein 
are  necessary.  Protein  is  also  used  to  furnish  energy,  and  it  may  be  used  for  the  produc- 
tion of  animal  fat;  but  protein  is  so  expensive  that  there  is  usually  no  profit  in  feeding 
it  for  those  uses. 

Fat  of  the  food  may  be  used  to  supply  energy,  or  it  may  be  transformed  into  ani- 
mal fat. 

Carbohydrates,  both  the  fiber  and  the  more  soluble  carbohydrate  extract,  are  used 
mainly  to  furnish  energy,  but  they  are  also  converted  to  a  considerable  extent  into 
animal  fat. 

It  should  be  borne  in  mind  that  fat  and  carbohydrates  serve  the  same  purposes  in 
animal  nutrition,  viz. — the  production  of  force,  heat,  and  animal  fat ;  while  protein 
serves  primarily  a  very  different  purpose — the  building  and  repairing  of  nearly  all  of 
the  working  parts  of  the  animal  body. 

In  calculating  the  values  of  foods  the  water  and  ash  are  usually  omitted,  but  the 
amount  of  digestible  protein  is  carefully  considered,  and  also  the  total  value  of  the 
digestible  food  as  a  source  of  energy.  This  power  of  food  to  furnish  energy  when 
burned  in  the  body  is  called  its  potential  energy  (sometimes  called  "fuel  value"),  and  it 
is  measured  in  "heat  units,"  which  are  called  calories.  A  calorie  is  the  amount  of  heat 
required  to  raise  the  temperature  of  one  kilo  (about  2.2  Ib.)  of  water  one  degree  centi- 
grade (1.8  degrees  F.).  The  potential  energy  of  one  pound  of  carbohydrates  or  of 
protein  has  been  found  to  be  1,860  calories,  and  of  one  pound  of  fat  4,220  calories. 

The  potential  energy  of  foods  is  given  in  the  last  column  of  Table  18. 


1896.] 


DIGESTION   EXPERIMENTS. 


207 


FEEDING  STANDARDS. 

One  of  the  important  things  to  keep  in  mind  in  making  up  rations  for  stock  feed- 
ing is  the  fact  that  protein  serves  a  special  purpose,  that  nothing  else  can  take  its  place, 
and  that  it  is  usually  the  most  expensive  constituent  of  the  food.  If  the  animal  is 
required  to  furnish  nitrogenous  products,  as  milk,  eggs,  or  animal  growth,  of  course 
much  more  protein  is  required  than  by  an  animal  which  is  not  producing  such  sub- 
stances; but  even  in  the  latter  case  experiments  have  shown  that  some  protein  is  neces- 
sary for  the  repair  of  the  tissues  of  the  body  which  are  broken  down  in  work  or  worn 
out  with  use.  Thus  protein  is  continually  required  by  the  animal. 

Another  important  fact  is,  that  the  animal  must  have  food  for  its  energy — food 
which  is  burned  in  the  body  to  furnish  heat  for  keeping  the  body  warm,  and  muscular 
power  for  internal  and  external  work. 

TABLE  19.     (From  Wolff's  Feeding  Standards.}     DAILY  REQUIREMENTS  FOR  1,000 
POUNDS  LIVE  WEIGHT  OF  ANIMALS. 


Protein, 
pounds. 

Potential 
energy, 
calories. 

Milk  cows  

2-5 

30,000 

Horses: 

1.8 

2.8 

27,000 
34,000 

At  heavy  work  

Oxen: 

0.7 
1.6 
2.4 

17,000 
25,000 
31,000 

At  heavy  work  

Fattening  oxen  : 

2-5 
3-o 
2.7 

35,000 
36,000 
35,000 

Second  period  

Third  period  

Growing  cattle: 

4.0 
3-3 

2.6 
2.0 

1.6 

42,000 
36,000 
33,000 
30,000 
27,000 

Of  500   u         u          "         "         

Of  850  tt         u          "         "       

Wool  sheep  : 

1.2 

1-5 

22,000 
25,000 

Finer  breeds  

Fattening  sheep  : 
First  period  

3-o 
3-5 

36,000 
36,000 

Second  period  

Growing  sheep: 

3-2 
2-5 

2.1 

1-4 

38,000 
31,000 
27,000 
23,000 

Of  67    "         "          "          >k     

Of  75    "         "          "          " 

Of  85    l                     "          "     

Fattening  swine: 

5-0 
4.0 
2.7 

60,000 
52,000 
38,000 

Third  period  

Growing  fat  swine: 
Of  50  Ib.  average  live  weight  

7.6 
5-o 
3-4 
2.5 

70,000 
56,000 
44,000 
35,000 

Of  100  "         "           "         u      

Of  170"         u           "         tt        

Of  250"         "           "         "      

208  BULLETIN  NO.   43.  [Aprtt,  1896. 

The  value  of  digestible  food  is  represented  by  the  protein  and  the  potential  energy. 
In  regard  to  the  amounts  of  food  an  animal  will  require  for  its  protein  and  potential 
energy,  much  will  depend  upon  what  is  required  of  the  animal.  The  food  required  by 
an  animal  which  is  at  rest  and  is  neither  growing  nor  fattening  will  not  supply  the 
needs  of  a  growing,  fattening,  or  working  animal,  or  of  one  that  is  required  to  produce 
milk  or  eggs.  Many  carefully  conducted  experiments  have  been  made  to  determine  the 
amounts  and  kinds  of  food  required  by  the  various  farm  animals  when  kept  for  different 
purposes.  From  the  results  of  these  experiments  there  have  been  worked  out  feeding 
standards,  that  is,  standard  directions  for  feeding.  The  feeding  standards  of  Dr.  Emil 
Wolff  are  widely  used.  These  are  given  in  Table  19. 

According  to  Wolffs  standard,  a  milk  cow  of  1,000  pounds  weight  requires  a  daily 
ration  which  represents  2.5  pounds  of  digestible  protein  and  30,000  calories  of  potential 
energy,  although  it  may  be  that  under  certain  conditions  it  is  not  the  most  profitable 
ration  for  the  dairy  farmer.  Of  course,  the  value  or  cost  of  food  and  the  selling  price  of 
the  animal  product  must  not  be  overlooked,  but  it  can  in  no  way  alter  the  truth  that  the 
cow  will  do  her  best  on  an  ideal,  or  well  balanced,  ration  ;  and  certainly  such  a  ration 
should  be  fed  if  it  can  be  done  at  no  extra  cost. 

By  referring  to  a  table  which  gives  the  pounds  of  protein  and  the  calories  of  energy 
furnished  by  different  foods  (see  Table  18)  it  is  a  simple  matter  to  make  up  a  desired 
ration.  For  example,  70  Ib.  of  cow  pea  ensilage  and  7.5  Ib.  of  wheat  bran  will  furnish 
2.5  Ib.  of  protein  and  30,000  calories  of  energy,  Wolff's  standard  ration  for  milk  cows  per 
1000  pounds  live  weight. 

Of  course,  these  food-stuffs  could  be  replaced  in  part  or  entirely  by  equivalent 
amounts  of  clover  hay  or  corn-fodder  and  corn  meal,  gluten  meal  or  any  other  suitable 
food  materials,  provided  that  the  full  ration  does  not  exceed  the  total  amount  of  food 
which  the  animal  will  eat. 

It  should  be  noted  that  this  bulletin  does  not  discuss  the  subject  of  animals,  but  it 
deals  only  with  the  question  of  foods. 

One  animal  may  eat  much  more  food  than  another,  even  though  they  are  of  equal 
weight,  and  are  offered  the  same  kinds  of  food.  This  difference  is  due,  of  course,  to  the 
individuality  of  the  animal.  The  one  is  said  to  be  a  " good  feeder,"  the  other  a  "poor 
feeder."  Or,  two  cows  may  eat  and  digest  equal  amounts  of  the  same  kinds  of  food,  and 
yet  one  cow  may  produce  much  more  butter  fat  than  the  other.  This,  again,  is  due  to 
the  animal  and  not  to  the  food.  Especially  do  animals  bred  for  different  purposes  show 
marked  differences  in  their  ability  to  make  milk  or  meat  from  equal  amounts  of  digested 
food.  Much  study  has  been  given  by  stock  breeders  to  these  animal  characteristics,  and 
they  are  important  considerations  ;  but  they  do  not  lessen  the  importance  of  providing 
sufficient  and  well  balanced  rations.  As  stated  before,  feeding  standards  are  derived 
from  the  results  of  many  carefully  conducted  experiments,  but  they  are  not  to  b£  regarded 
as  infallible  conclusions  strictly  applicable  to  every  condition  of  stock  raising.  They 
are  intended  not  to  replace  but  to  supplement  the  intelligence  of  the  stock  feeder. 

CYRIL  G.  HOPKINS,  M.  S.,  Chemist. 


UNIVERSITY  OF  ILLINOIS-URBANA 


